FUNGI PARASITIC UPON ALEYRODES GITRI 
 
 By 
 HOWARD S. FAWCETT 
 
 A THESIS FOR THE DEGREE OF MA.- 1 -CIENCK 
 
 SUBMITTED TO THE FArUKT 
 
 THE UNIVERSITY OF THE STATE OF FLORIDA 
 
 JUNK, 1908. 
 
FUNGI PARASITIC UPON ALEYRODES CITRI 
 
 TTt-\~' 
 
 U'NrvEK 
 
 -or 
 
 ' 
 
 By 
 
 HOWARD S. FAWCETT 
 
 A THESIS FOR THE DEGREE OF MASTER OF SCIENCE 
 SUBMITTED TO THE FACULTY OF 
 
 THE UNIVERSITY OF THE STATE OF FLORIDA 
 
 JUNE, 1908. 
 
UNIVERSITY OF THE STATE OF FLORIDA 
 SPECIAL STUDIES No. i 
 
CONTENTS. 
 
 ENTOMOLOGY 
 UBfiABY 
 
 PAGE. 
 
 I. INTRODUCTION 5 
 
 Statement of Work on Which the Thesis is Based 777 . . . ,-rv . . , 5 
 
 Historical Review of Entomogenous Fungi 5 
 
 Historical Review and Economic Status of Aleyrodes citri R. & H 8 
 
 II. ASCHERSONIA ALEYRODIS WEBBER 10 
 
 Discovery and Description 10 
 
 History 10 
 
 Methods of Introduction 11 
 
 Germination of Conidia 12 
 
 Cultures 13 
 
 Infection of Aleyrodes citri from Cultures 16 
 
 Distribution 17 
 
 III. ASCHERSONIA FLAVO-CITRINA P. HENN 11 
 
 Discovery and Description 11 
 
 Comparison with A. aleyrodis 18 
 
 Cultures 18 
 
 Germination of Conidia 39 
 
 Super-parasite 21 
 
 List of Localities in Florida 21 
 
 IV. VERTICILLIUM HETEROCLADUM PENZ 21 
 
 Discovery and History 21 
 
 Description 22 
 
 Cultures 23 
 
 Germination of Conidia 24 
 
 Infection of Aleyrodes citri from Cultures 24 
 
 List of Insects Parasitized, with Localities 25 
 
 V. Sl'H AEROSTILBE COCCOPHILA Tui 25 
 
 Description 25 
 
 History 26 
 
 Relation to San Jose and Other Scale Insects 27 
 
 Parasitism on Aleyrodes citri 28 
 
 List of Insects Parasitized, with Localities 29 
 
 VI. M ICROCERA SP 29 
 
 Technical Description ' 29 
 
 Discovery 30 
 
 Cultures 30 
 
 Infection of Aleyrodes citri from Cultures 32 
 
 Germination of Conidia 33 
 
 Variation in size of Conidia 33 
 
 Distribution in Florida 34 
 
 VII. THE "BROWN FUNGUS" 34 
 
 Discovery 34 
 
 Description by Webber 34 
 
 Brown fungus of Parkin 35 
 
 Methods of Introduction 35 
 
 Distribution 36 
 
 SUPPLEMENTARY NOTES 36 
 
 SUMMARY ?>1 
 
 BIBLIOGRAPHY :58 
 
 EXPLANATION OF PLATES.. 41 
 
 272696 
 
LIST OF ILLUSTRATIONS. 
 
 PACK. 
 
 Fig. 1. Adult and egg of .llcyrodcs citri facing 8 
 
 Fig. 2. Larvae and pupae of Alcyrodcs citri : facing 9 
 
 Fig. 3. Conidia of Aschcrsonia alcyrodis 12 
 
 Fig. 4. Conidium of Aschcrsonia alcyrodis germinating 13 
 
 Fig. 5. Hyphae of Aschcrsonia flaro-citrina H 
 
 Fig. 6. Conidia of Aschcrsonia flaro-citrina 1 ( .) 
 
 Figs. 7, 8 and 9. Sporids of Aschcrsonia flavo-citrina 20 
 
 Fig. 10. Conidiophores and conidia of / 'crticilliitm hctcrocladnin 23 
 
 Fig. 11. Spore-like bodies of I 'crticillinin hctcrocladnin 23 
 
 Fig. 12. Perithecium of Spkaerostilbe coccophila 2,~> 
 
 Fig. 13. ASCIIS of Sphacrostilbc coccophila 2."> 
 
 Fig. 14. Sporodochium of $j hacrostilbc coccophila 2(5 
 
 Fig. 15. Conidia of Sphacrostilbc coccophila 26 
 
 Fig. 16. Hypha and conidia of Microccra sp 30 
 
 Fig. 17. Conidia of Microccra sp 30 
 
 Fie. 18. Conidia of Microccra sp 30 
 
 Fig. 19. Sporids of Microccra sp 33 
 
 Figs. 20. 21. 22 and 23. Cultures of . Ischcrsonia alcyrodis Plate I 
 
 Fig. 24. .Ischcrsonia flaro-citrina on Citrus leaf Plate II 
 
 Fig. 23. .Ischcrsonia alcyrodis on Citrus leaf Plate II 
 
 Figs. 26 and 27. Cultures of . Ischcrsonia flaro-citrina '. Plato 1 1 1 
 
 Figs. 28, 29 and 30. Cultures of Aschcrsonia flaro-citrina Plate IV 
 
 Fig. 31. / 'crticillinin hctcrocladnin on Citrus leaf Plate IV 
 
 Figs. 32, 33 and 34. Cultures of / 'crticillinin hctcrocladnin Plate V 
 
 Fig. 33. / 'crticiliinin hctcrocladnin on leaf Plate V 
 
 Fig. 36. Sphacrostilbc coccophila on . Ispidiotns hcdcrac Plate VI 
 
 Figs. 37 and 38.Sphacrostilhc coccophila on Mytilasfiis citricola Plate VI 
 
 Figs. 39 and 40. Cultures of Microccra sp Plate VI 
 
 Fig. 41. Microccra sp. on Citrus leaf Pl atc yj 
 
 Fig. 42. Brown Fungus on Citrus K-af Pl ate yjj 
 
 HH. 43. Super-parasite on Aschcrsonia flaro-citrina Plate VI I 
 
FUNGI PARASITIC UPON ALEYRODES GITRI. 
 
 BY 
 
 HOWARD S. FAWCETT, 
 Plant Pathologist, Florida Agricultural Experiment Station. 
 
 I. INTRODUCTION. 
 
 Since taking up the investigation of Citrus diseases in the fall of 1905, 
 in connection with work in the Florida Experiment Station, the author has 
 given considerable attention to the study of the fungi parasitic on Aleyrodes 
 citri R. & H., and on scale insects. Since the beginning of the work three 
 species of fungi have been discovered to be parasitic upon the larvae and 
 pupae of Aleyrodes citri; two of these, Aschcrsonia flavo-citrina, and an 
 undetermined species of Microcera, were first noticed by Prof. P. H. Rolfs, 
 and the third, Vcrticillium hctcrocladum, by the author. With the addition 
 of these three, the number of known fungus parasites of this insect is in- 
 creased to six, namely: 
 
 1. Aschcrsonia alcyrodis Webber, 
 
 '2. Aschcrsonia flavo-citrina P. Henn., 
 
 3. J^crticilliuni hctcrodadnin Penz., 
 
 4. Spkaerostilbe coccophila Tul., 
 .">. Microcera sp., 
 
 (>. The sterile Brown fungus of Webber. 
 
 Cultures of all these fungi except the Brown fungus have been grown in 
 the laboratory by the author. One of these, Sphaerostilbe coccophila., had 
 been previously studied in pure cultures by P. H. Rolfs, who published his 
 results in Bulletin 41 of the Florida Experiment Station under the title of 
 "A Fungus Disease of the San Jose Scale". For this reason a further study 
 of this fungus in cultures was not undertaken, and it is, moreover, only 
 rarely parasitic upon Aleyrodes citri. 
 
 It is the purpose of this thesis, after a brief review of previous investiga- 
 tions of the fungus parasites of insects, to describe the results of recent study 
 of the fungi that are parasitic upon Aleyrodes citri in Florida. With the 
 description of each fungus there is given its distribution and the names of 
 its insect hosts. A bibliography of the six fungi is added. The illustrations, 
 except Figs. 1, 2, and 42, are original. Technical descriptions and a general 
 review of previous literature, when any such has been published, are in- 
 cluded with the account of each fungus. 
 
 ENTOMOGENOUS FUNGI. 
 
 The fact that certain low forms of plant growth, such as fungi and 
 bacteria, are at times the cause of the destruction of great numbers of 
 insects, has created much popular as well as scientific interest for many 
 
G l-r.\V.l PARASITIC UPON ALKYRODKS CITRI. 
 
 years. As early as 1T54, according to M. C. Cooke, 1 a popular description 
 was written by Father Torrubia of a fungus growing out from the bodies 
 of wasps. Father Torrubia had collected specimens of this at Havana, 
 Cuba, as early as 1749. Cooke thinks that this fungus was Cordyceps 
 specocephala. lie quotes Torrubia's account from Edwards' "Gleanings 
 in Xatural History," published in 1<5S, and says that this species represents 
 the rather celebrated vegetable wasp which had a romantic history a century 
 l.efore. Cooke also gives an account of a species of Isaria, which had been 
 known as early as 1782 on the Sphinx moth. 1 He mentions as many as 
 1!7 species, representing 39 genera of fungi, that have been found growing 
 upon various insects. The majority of these species are included by Cooke 
 under ."i genera: Cordyceps, with 48 species; Laboulbenia, with 34 species; 
 Isaria, with 2\ species; Entomophthora, with 22 species; and Empusa, with 
 13 species. Since then main new genera have been added to the ento- 
 inngencms fungi. Species of Cordyceps found on wasps, bees, ants, cater- 
 pillars, and scale insects, have been mentioned by many scientists and 
 popular writers from the last-mentioned date down to the present time. 
 Cooke refers to the "History of Insects" by Murray, published in 1838. as 
 containing interesting accounts of fungi growing upon insects. 
 
 The Tulasne brothers were probably among the first to study the para- 
 sitism of these fungi. They published descriptions of some of them in 
 L857, a and of others in isii.").-' Among those described in 1865 was Sphaer- 
 ostilbc cticcophila Tul.. which is one of the species treated of in this thesis 
 as sometimes parasitic on Alcyrodcs citri. The work of Pasteur on the 
 flacherie of the silkworm, marked a great advance in our knowledge of 
 insect diseases. This disease was due to a species of bacterium. Pasteur's 
 work was taken up with the view of protecting the insect from parasitic 
 growth, while most subsequent work has been carried on with the view of 
 destroying insect pests by means of their parasites. A work of much scien- 
 tific importance was that of Roland Thaxtcr, :: "The Entomophthoraceae of 
 the I'nited States", published in 1888. The genera which he studied attack 
 flies, beetles, moths, caterpillars, grasshoppers, and plant lice. 
 
 Since the institution of Experiment Stations in the United States, ex- 
 periments have been made with several species of fungi, with a view of 
 using them in combating insect pests. l"p to this time the greatest degree 
 of Miccess has l;een attained in Florida, where the conditions of temperature 
 and moisture are conducive io the spread of fungi. The use of fungi to 
 combat insect peMs has met with only limited success in the Northern States. 
 A number <>f years agn the employment of a species of Sporotrichum for 
 spreading disease among chinch-bugs received much attention. Tn 1895. 
 
 'Vegetable Wa>p> and Plant Worm-. pp. U-48, London. ls.:.. 
 
 2 Cookr. M. C' \Ym-ialili- Waspv and IMant Worms. ,,],. ;,, :;;; n 73 <,<; j |- ]s -. , n( > 
 
 881. 
 'Mi-moil-* of tin- P,.,MOH Soi-irtv of Natural History. Vol. IV. Xo. 6. 
 
INTRODUCTION. 7 
 
 S. A. Forbes 4 of the Illinois Experiment Station gave a detailed account of 
 cultures and infection experiments carried on with this fungus. A few 
 sentences from his discussion of the results are here quoted: 
 
 The white muscadine will not spread among vigorous chinch-bugs in the field in 
 very clrv weather to an extent to give this disease any practical value as a means of 
 promptly arresting serious chinch-hug injury under such conditions. : 
 
 It is most likely to catch in low spots, where the soil is kept somewhat moist by 
 dense vegetation, a mat of fallen herbage, or the like. * * * 
 
 If decidedly wet weather follows upon its introduction, even after an interval of 
 several weeks, it is likely to start up and take visible effect ; but continuous rains, 
 depressing the vital energies of the insect, seem commonly requisite to its efficient 
 action. 
 
 Some investigation has been carried on with a number of other ento- 
 mogenous fungi grown in pure cultures. G. F. Atkinson 5 and R. H. Pettit 6 
 studied cultures of Cordyceps, Isaria and Sporotrichuin. R. H. Pettit in 
 his bulletin issued in 1895 included a long bibliography of the literature on 
 entomogenous fungi, to which any one interested in the history of this 
 subject is referred. 
 
 In 1897, P. H. Rolfs, 7 in his bulletin "A Disease of the San Jose Scale," 
 demonstrated that the fungus Sphaerostilbc coccophila could be used in a 
 practical way in combating the San Jose scale in Florida. In 1906, a valu- 
 able paper by J. Parkin, 8 "Fungi Parasitic on Scale Insects," gave a general 
 review and the distribution of the fungus parasites of Coccidae and Aley- 
 rodidae which had been described in all countries up to that time. He 
 referred to a recent publication by Gueguen 9 in France, which is said to be 
 an exhaustive work on the fungus parasites of man and animals. A recent 
 contribution by Dop 1 " on a new fungus parasite in Martinique that has 
 saved the cocoanut industry of that island is also briefly mentioned. 
 
 In Florida, insects belonging to the orders Coccidae and Aleyrodidae 
 are very subject to attacks of fungi. In addition to the six fungus parasites 
 of Alcyrodcs citri here treated of, there are two other fungi which are not 
 found on this insect, although they are quite common on scale insects of 
 Citrus. These are Ophioucctria coccicola E. & E., and Myriangiuw duriaci 
 Mont, both of which are illustrated in Bulletin 94 of the Florida Experi- 
 ment Station. Webber also found on the wax scale Ceroplastcs florldcns'is, 
 the fungus Aschcrsoma turbinata; and he mentions finding on various in- 
 
 4 Experiments with the Muscadine Disease of the Chinch-bug, etc., 111. Agr. Exp. Sta., 
 
 Ikil. :;s, 1S95. 
 
 5 Artificial cultures of an Entomogenous Fungus. Bot. Gaz., Vol. XIX, pp. 129-145, 1894. 
 h Studies in Artificial Cultures of Entomogenous Fungi. Cornell Univ. Agr. Exp. Sta. 
 
 Bui. 97, 1S95. 
 
 7 A Fungus Disease of the San Jose Scale. Fla. Agr. Exp. Sta. Bui. 41, 1897. 
 
 8 Annals of Roy. Bot. Card. Peradeniya, Vol. 3, Part 1. 
 
 9 Gueguen, F. Les Champignons parasites de I'homme et des animaux, pp. 252, Paris, 
 
 1904. Bot. Centralbl., XCVI, p. 044. 
 
 " Dop, P. Bull. Sci. France et Belgique. XXXIX, p. 1P>5, 1905. Bot. Centralbl., XCIX, 
 p. 50.*). 
 
> I-l'Ni'.I PARASITIC UPON ALEYRODES CITRI. 
 
 sects other Aschersonias, which, as far as we know, he has not identified. 
 I'mf. II. II. Hume sent to the author in 1906 a species of Aschcrsonia found 
 mi what appeared to he an Alcyrodcs on the leaves of Hc.v Dahoon. It is 
 (|iiite probable that further observation will reveal a number of other species 
 >f fungi parasitic u])nn insects of these two orders in Florida and the ad- 
 joining S:au--. 
 
 AI.KYKDDES CITRI. 
 
 ffhis insect, the larval and pupal stages of which are parasitized by the 
 fungi to he discussed later, has been a serious pest of orange groves in 
 Florida and the adjoining States for a number of years. It had been ob- 
 served by C. Y. Riley in 1878 in the greenhouses at the United States De- 
 partment of Agriculture at Washington. In 1885, Mr. Ashmead wrote an 
 account of it for the "Florida Despatch", in which he gave it the name of 
 Alc\rodcs citri. In 1895, Riley and Howard 11 first described this species 
 in "Insect Life". In this publication it is reported as having been received 
 from Mississippi. Louisiana, North Carolina and many points in Florida, 
 (xainesville and Crescent City are places mentioned at which it had been 
 studied by Jas. Yoyle and H. G. Hubbard, before 1893. It is also stated that 
 during the years 1892 and 189;? it had so multiplied in parts of Louisiana and 
 Florida as to deserve immediate attention. It is of interest here to note that 
 it was about this time. IS!):?, that Webber discovered the first fungus para- 
 site of this insect. 
 
 This insect is not a true fly, as the name might imply, but belongs to 
 the Order I lemiptera, which also includes the plant lice and scale insects. 
 Tlie following summary of the life-history of Aleyrodes citri is from Bul- 
 letin ss nf the Florida Agricultural Experiment Station, by E. W. Berger : 
 There are three well-defined broods of the whitefly, with an interval of several 
 da\s t.. several weeks hetweeii each brood, when few or none are seen on the wing. 
 The first brood generally appears some time during March, April or May; the second 
 during June. Jul\ or August; and the third during September and October. 
 
 Larvae and pupae of the whitelly are to be found on the under surfaces of the 
 leave-, and seldom elsewhere. The larvae are scale-like and closely appressed against 
 tile leaf. They vary in si/e from the very young, just visible to the unaided eye, to the 
 fully matured larvae which measure about one-sixteenth of an inch in length. 
 
 The larvae are white and translucent with a tinge of yellow, and almost invisible 
 
 upon the leal. The pupa (Fig. :. X... s) is the transformation stage from the larva 
 
 to the adult winged tly. The pupae are readily visible as yellowish-white, plump, oval 
 
 b-,di,.^with a dark reddish sp.,t on the back. From the pupa emerges the adult winged 
 
 Tin- little white cases, with a T-shaped split on the back, found on the under 
 
 ; a leal, are tin- empty pupa cases from which the adults have emerged (Fig. 
 
 No, in). The eggs <Fi. ,. N08, 3 and ft) are JUS1 visible to the unaided eye as a 
 upon the nndrr surface ,,f ,h e leaves. An ordinary hand lens will show 
 them as little egf-shaped bodies iniu-h resembling grains of wheat. * * * 
 
Fig. 1. AlJvYRODES CITRI.* 
 
 No. 1 and 2, Adult female; No. :-i. Egg; No. 4, Egg-shell; No. 5, Claspers at tip of 
 abdomen of male; No. 6, Antenna; No. 7, Fore margin of front wing. 
 
 INSECTS SOMETIMES MISTAKEN FOR ALEYRODES CITRI. 
 
 No. 8, Larva of Alcyrodcs floridcnsis; Nos. <) and 10, Margin of larva; No. 11, Larva 
 of Lccaniuin hesperidum. 
 
 From Fla. Agr. Exp. Sta. Bui. 07, by H. A. Gossard. 
 
Fig. 2. ALEYRODES CITRI.* 
 
 No*. 1 and :->. Larva first stage, at different magnification* ; No. 3, Larva, second stage - 
 No. 4. Larva third stage; No. 5, Larva, fourth stage; No. .;. Margin of advanced 
 larva; No. 7, Vasiform orifice of fourth stage; Xo. s, Pupa; No. 0, Adult emenrine 
 tn.ni pupa-case; No. 10, Empty pupa-case. 
 
 *From Fla. Ayr. Kxp. Sta. I'.ul. c,7, by H. A. Gossard. 
 
INTRODUCTION. 9 
 
 Twenty thousand eggs have been estimated on a large orange leaf. From observa- 
 tions made in the laboratory, egg-laying begins when the female is from eighteen to 
 thirty hours old ; and from seventeen to twenty-five eggs are deposited. These eggs 
 are generally all laid within twenty-four hours after the first egg has__hen laid. Her 
 length of life has been estimated at from three days in warm weather to three weeks 
 in cool weather, and the complete length of life cycle from egg to adult is from forty 
 or fifty days in summer to six months in winter. 
 
 The origin of the whitefly pest in Florida is only a matter of con- 
 jecture. It is not definitely known whether it is a native species or was 
 introduced from the East. A recent report that Aleyrodes citri has been 
 discovered in Asia gives some weight to the latter view. H. A. Gossard, 
 in Bulletin (>T of the Florida Experiment Station, "The Whitefly", 1903, said 
 with regard to its advent in Florida : 
 
 The fly seems to have been first known in Florida throughout the region comprised 
 in Volusia, Marion, Lake, Alachua, and Orange counties ; from which, I have little 
 doubt, it was transferred to Manatee county and to local centers along the northern 
 borders of the State. 
 
 It had therefore become widely distributed before it attracted any consid- 
 erable attention. At the present time it is widely distributed in many parts 
 of Florida, and is spreading slowly to parts not before infested, in spite of 
 the work that is done by the growers to keep it out of the groves. 
 
 Several investigations are being carried on at the present time by the 
 Florida Experiment Station, and by the United States Department of Agri- 
 culture in order to work out practical methods of controlling the pest. 
 Spraying with insecticides, fumigation with hydrocyanic acid gas under 
 tents, and infection with fungus parasites have all been used. Fumigation 
 and fungus infection are the most promising remedies known at the present 
 time. The use of the fungus parasites in destroying this insect will be 
 briefly discussed later, when the various fungi are described. 
 
 The most serious injury caused by the whitefly is the sooty mold that 
 always follows the insect. This is a species of Meliola, a soot-colored 
 fungus that lives in the honeydew secreted by the whitefly larvae. Since 
 the larvae are found upon the under surfaces of the leaves, the honeydew 
 collects upon the upper surfaces of the leaves below and furnishes a suita- 
 ble medium for the growth of Meliola. The sooty mold spreads in a black 
 layer over the surface. The fruit is also blackened, so that it must frequently 
 be washed before it is shipped. The vitality of the tree is lowered, not 
 only by the loss of the nourishment sucked out by the insects, but also by 
 the shutting off of the sunlight from the surfaces of the leaves. An account 
 of this fungus is given by Webber in Bulletin 13 of the Division of Vegetable 
 Physiology and Pathology, Washington, D. C. 
 
10 FUNGI PARASITIC 1'1'ON AI.KYKODKS CITRI. 
 
 II. ASCHERSONIA ALEYRODIS WEBBER. 
 
 This species was first discovered by H. J. Webber in August, 18913, at 
 Crescent City, in the grove of J. H. Harp. Mr. Webber 12 published a pre- 
 liminary notice of the entomogenous nature of this fungus in 1894, referring 
 it to Aschcrsonia tahitcnsis Mont. In 189(5, under the same name, he 
 mentions it in the bulletin, "The Principal Diseases of Citrus Fruits in 
 Florida". 1:I Finding it after further study to be a distinct species, he de- 
 scribed it in 1897 in his bulletin, "Sooty Mold of the Orange and its Treat- 
 ment," as Aschcrsonia alcyrodis,' 14 as follows: 
 
 .Ischcrsonia alcyrodis Webber. Stroma hypophyllous, depressed hemispherical, 
 pinkish buff or cream colored, coriaceous, 1 2Vmm. in diameter ; mycelial hypothallus 
 grayish white, forming a thin membrane closely adhering to the leaf and extending 
 about 1 mm. beyond the stroma ; perithecia membranaceons, at first superficial, later 
 becoming immersed, irregular, reniform or orbicular in mature specimens, and opening 
 by small, round, or elliptical pores or slits; basidia crowded, filiform, slender, con- 
 tinuous, 28 40 microns long, 0.94 1.5 in diameter; paraphyses abundant, slender, 
 projecting beyond the basidia, 65 100 microns long, y 1 micron in diameter; spor- 
 ules fusiform, continuous, mucilaginous, hyaline, sometimes obscurely 3 4 guttulate, 
 9.4 14.1 microns long by 0.94 1.88 microns wide, very abundant and erumpent, form- 
 ing conspicuous coral red or rufus masses. (Parasitic on Alcyrodcs citri R. & H. infest- 
 ing citrous leaves in Florida). 
 
 HISTORY. 
 
 Some species of Aschersonia have been reported to be conidial stages of 
 the genus Hypocrella, an Ascomycete. Massee 13 speaks of having shown 
 that the ascigerous forms of species of Aschersonia were produced on fallen 
 leaves on which the conidial stages had grown. Parkin 10 also mentions this 
 genus as the probable perfect stages of species of Aschersonia and refers 
 to a species of Hypocrella (H. Raciborskii) described by Zimmerman, 17 
 with a conidial stage referable to Aschersonia. No ascigerous forms have 
 as yet been discovered in connection with the Aschersonias in Florida. 
 
 In I'.KI."), F. S. Earle ls reported Aschcrsonia alcyrodis on Alc\rodes 
 citri in Cuba. In I'.MM;. J. Parkin 10 reported finding an Aschersonia on sev- 
 eral undetermined species of Aleyrodes in Ceylon, which closely resembled 
 Aschcrsonia alcyrodis. He said, "Numerous forms of Aschersonia have 
 been found in Ceylon on species of Aleyrodes and Lecanium". In February, 
 I'.Kis. Cook and Home 20 reported Aschcrsonia alcvrodis on .llcvrodcs citri 
 and on Ale\rodes howardi'i, in Cuba. 
 
 "Webber, H. J. Journal of Mycology, V<>1. VI, No. 4, p. :;<;:;. \ 
 
 13 WeblK-r, II. J. Div. of Veg. Phys. & Path., Bui. s, p . ;_>;. Washington I) C L896 
 "Webber, H. J. Div. ,,f YY-. Phys. & Path.. I'.ul. L3, p. 21, Washington I") C*. ls7 
 "Massee, G. Jour. Hot. V>1. 34, i. 151. 
 10 Parkin, J. Ann. Roy. Bot. Card. IVradtniya. V.>1. III. Part 1 pp <) and 3> I'.MII, 
 
 17 Zimmerman. Central!), fiir I'.akt.. Abth. II. Vol. VII. p. 872. 
 
 18 Primer Informe Anual de la Estarion Central . \-ronoinica <lr Cuba 1WM and l')<r> 
 
 p. 169, I'.ioii. 
 
 "Annals Roy. Bot. Card. P< radnm a. Vol. III. Pan I. p. ;;;. l<t<m. 
 "Cook, M. 'l\. and llornr. \\'. T. Cuban K\p. Sta. P.nl. ( .i. p. :;l. 1908. 
 
ASCHERSONIA AIvEYRODIS. 11 
 
 Previous to Webber's publication, 21 the entomogenous nature of the 
 genus Aschersonia was not known, although up to that time__there were 19 
 species of this genus described, as recorded in Saccardo's "Sylloge Fun- 
 gorum". This species was therefore the first known parasite of Aleyrodes 
 citri, and was probably the first fungus that had been reported on any 
 species of Aleyrodes. In the course of his investigations on the sooty mold, 
 Webber reported that he had found three other species of Aschersonia, 
 parasitic on other insects in Florida ; one of which was Aschersonia tur- 
 binata on the Wax Scale (Ceroplastes floridensis Comst.). The others 
 were not determined by him. In 1897, when he wrote his bulletin on sooty 
 mold, Webber reported that Aschersonia aleyrodis was found in Florida 
 at Crescent City, Bartow, Panasoffkee and Gainesville. He also stated that 
 no sign of the fungus was apparent in groves infested with Aleyrodes citri 
 at Ocala, Orlando, Evinston and Ormond. In the same bulletin, the de- 
 velopment of the fungus, the probable method of spore dissemination, and 
 the methods of introducing the fungus on the orange trees, are discussed 
 at some length. The description of the development of the fungus in the 
 next paragraph is taken with slight changes from this bulletin. 22 
 
 The first indication of the effect of the fungus on the larva of the whitefly is 
 the appearance of slightly opaque, yellowish spots unusually near the edge of the 
 larva. In the early stages of infection the larva becomes noticeably swollen, and appears 
 to secrete a greater abundance of honeydew than normally. As the fungus develops, 
 the interior organs of the larva appear to contract away from the margin, leaving a 
 narrow circle, which becomes rilled with hyphae. Shortly after this the hyphae burst 
 out around the edge, forming a dense marginal fringe. This may form all around 
 the larva at about the same time, or develop at one portion of the margin sooner than 
 the others. Death usually ensues, it is believed, before the hyphae burst out. Tne 
 fungus does not spread over the leaf to any extent, but grows upward in a mass, 
 gradually spreading over the larval scale. It is not uncommon to find the pycnidia, with 
 their bright coral-red masses of sporules, formed in a circle around the edge of the 
 larva while it is yet visible. As the Aschersonia develops, the hyphae spread over 
 the larva forming a dense compact stroma, which ultimately entirely envelops the 
 larva. The stroma in this stage is thin and disk-like, the fructification being usually 
 borne in a circle near the edge. The hyphae, which make up the main mass of the 
 stroma are from 8.5 to 7.5 micro-millimeters in diameter. Within the body of the 
 insect and near the pycnidia they are somewhat smaller. 
 
 METHODS OF INTRODUCTION. 
 
 Two methods of introducing the fungus into groves infested with 
 Aleyrodes citri were used by Webber with fair success. (1) Pinning 
 fungus-bearing leaves into trees infested with Ale\rodes citri, in such a 
 way as to cause the fungus spores to come in contact with larvae not yet 
 infected. (2) Planting small trees with fungus infected larvae in a grove, 
 so that the fungus-bearing leaves came in contact with the leaves on which 
 
 21 Webber, H. J. Div. of Veg. Phys. & Path.. Bui. 13, p. 20, Washington, D. C., 1897. 
 "Webber, H. J. Div. of Veg. Phys. & Path., Bui. i;$, pp. 23-24, Washington, D. C, 
 1 S<)7 
 
1\! i'l'XC.I PARASITIC ri'O.N AI.K.Vkt >!>KS CITRI. 
 
 it was desired to start the fungus. Further methods of introducing this 
 Asclvrsmiia by spraying the trees with water containing fungus spores, 
 obtained either from previously infected larvae or from artificial cultures, 
 have been recently carried on by E. W. Berger 2 ' 5 of the Florida Experi- 
 ment Station. Webber 24 had tried infecting larvae by spraying a mixture of 
 conidia in water, but had failed to reproduce the fungus in this way. E. W. 
 I Merger has found that to succeed with this method it is best to have a spray 
 pump that contains no copper parts, and that has also not been previously 
 used for spraying fungicides or insecticides. Fairly good infection of this 
 fungus has been obtained bv Merger, by the spore-spraying method, at St. 
 Petersburg, Leesburg. New Smyrna, Gainesville and Lake City. The fact 
 that infections may be made from cultures that have grown under artificial 
 conditions in the laboratory for long periods of time, suggests the possi- 
 bility of using these cultures in a practical way at the very beginning of 
 the rainy season, when fresh fungus on leaves is hard to obtain. Consid- 
 erable quantities of this fungus may be grown artificially on various media, 
 as will be shown in the following pages. 
 
 C.Kk.M I. NATION OF CONIDIA. 
 
 Conidia of this fungus were germinated in hanging drop cultures of dis- 
 tilled water, tap water, and various solutions of glucose. In all of these 
 cultures the germination was very slow, scarcely ever beginning in less 
 time than v?n hours. Germination in distilled water and tap water was very 
 feeble, while that in solutions of glucose was much stronger, as is explained 
 more fully under the germination tests for Aschcrsonia flaro-citrina. 
 
 Trials were made at various times to germinate spores in hanging drop 
 cultures from pustules that had dried in the atmosphere of the laboratory. 
 The following is a record of these tests: 
 
 /7 1. On November K), l!)()(i. cultures were made from 
 
 // leaves collected on October IV. I'.HH;, which had remained 
 
 /I in the laboratory vs days. The tests were made in glucose, 
 1 1 in distilled water, and in tap water. On December 11 (31 
 days) sporids formed in : per cent, glucose. The growths 
 Fit:.:;. "i distilled water and in tap water had not proceeded far 
 
 " IIH SL - ( > January 5, 1907, cultures were made from leaves 
 
 nonn 
 
 collected October IV, lixxi, which had remained in the 
 
 laboratory for s.~> days. The test was made in distilled water. \o germina- 
 tion took place. 
 
 ' Fl;i. Kxp. Sta. Bui. 88, ].p. 57-63, I'.MM;. 
 
 "Webber, II. J. Div. of Veg. Phys, \- Path., Bui. 13, p. :>;. Washington, D. c. 
 
ASCHERSONIA ALEYRODIS. 13 
 
 3. On April 18, 1907, cultures were made in tap water from leaves 
 collected October 12, 1906, which had remained in the laboratory 189 days. 
 No germination took place. CZlr"::'" '""**^ 
 
 4. On April 18, 1907, cultures were made in tap "^""^^S^niX^ 
 water from leaves collected on December 12, 1906, Fig. 4. conidiumof Ascher- 
 which had remained in the laboratory 128 days. No gftSSSftg^; SK 
 germination took place. tion at 25c.. x 1000. 
 
 5. On April 18, 1907, germination trials were made from a culture 
 isolated December 7, 1906, which was transferred to potato on January 14, 
 1907, and had not entirely dried out. A few spores germinated. 
 
 CULTURES. 
 
 Pure cultures of Aschersonia aleyrodis were first obtained in January, 
 1907. On December 7, 1906, petri dishes of neutral 5 per cent, glucose agar 
 were poured. These were made by introducing into the melted agar a 
 platinum loop, that had been thrust several times into a test-tube containing 
 spores from several stromata shaken up in sterile water. In the first dilu- 
 tion, on January 5 (29 days), at a temperature of 15 to 25 C., minute 
 fungus mycelia appeared, yellow in the center, with a fringe of delicate 
 white hyphae projecting outward. On January 8 .(32 days), the largest 
 of these had turned red in color. They were raised, hemispherical, and 
 had the upper surface dotted with little white lumps. Larger stromata were 
 2 to 4 mm. in diameter. On January 15 (39 days) the stromata were 5 
 to 7 mm. broad, with a wide fringe of straight hyphae projecting outward 
 over the agar. The stroma by this time contained pycnidial cavities with 
 spores (Plate I, Fig. 20). 
 
 On April 10, 1907, this fungus was again isolated. Leaves were picked 
 at Orlando, on April 6. Pustules were broken up in water in a watch-glass, 
 and a dilution set of three petri dishes A, B and C, was poured with agar 
 (1 per cent, normal acid to phenolphthalein) , to which 5 per cent, glucose 
 sugar had been added. Petri dish A was overrun with bacteria and quick- 
 growing fungi. Petri dish B contained, on April 26 (16 days), about 50 
 centers of growth just beginning, and a few bacteria. Petri dish C, on 
 April 26 (16 days), contained no visible growth. On May 11 (31 days), 
 C contained a fine growth of 11 mycelia, which probably first showed a few 
 clays before. No further record was kept. 
 
 On September 23, 1907, this fungus was isolated for the third time in 
 petri dish cultures A, B and C. Four or five small pustules were shaken 
 up in 7 cc. of water until it became milky in appearance. Five loopfuls w r ere 
 washed into A, etc. A was contaminated with other fungi, C developed one 
 mycelium of A. alcyrodis, and one of another fungus. Petri dish B devel- 
 oped a pure culture as follows: On October 8 (15 days), one point of 
 growth was just appearing. On October 18, there were four mycelia, five 
 to six mm. in diameter, with rings of reddish pycnidia ; and seven others 
 just starting. On October 28 (35 days), twenty very red pustules with 
 abundant spores and light gray fringes of outgrowing hyphae had de- 
 veloped. 
 
 From these isolation tests, it appears that on 5-10 per cent, glucose agar 
 in the laboratory, it requires from 30-40 days for the fungus to mature a 
 pustule and produce pycnidia. This time corresponds somewhat closely 
 to the time for the fungus to develop upon larvae of Ale\rodc$ citri, as 
 
1 t l-l NC.I I'AKASITIC fl'UN Al.KYKODKS CITRI. 
 
 shown by the infection experiments of K. \V. Uerger. (See Bulletin 88. 
 Florida Experiment Station, pp. .*>;. oS.) The fungus is extremely slow in 
 developing in the petri dishes, thus increasing the liability to contamination 
 with other fungi and bacteria. Its slow-growing habit demands therefore 
 a strictly pure culture, since the rapidly growing fungi and bacteria will 
 otherwise crowd it out completely. 
 
 The many previous failures of the author and of others before him to 
 grow this fungus in cultures, were probably due to the fact that the petri 
 dishes were rejected too soon, or were allowed to dry out before the spores 
 had time to form mycelia and stromata. This fungus was transferred from 
 petri dish cultures to test-tubes of sweet potato (Plate I, Fig. 22), Irish 
 potato, rice, white cornmeal (Plate 1. Figs. 21, <M). and bread. On all 
 of these media, the growth was similar in general appearance to the growth 
 of Aschcrsonia flat'o-citrina. except that the color of the stroma and spore- 
 masses was red instead of yellow. The most luxuriant growth was on sweet 
 potato plugs. The characteristic red color of the fungus stroma rarely ap- 
 peared on Irish potatoes. This would seem to indicate that sugar was 
 necessary for the proper development of both the red pigment of Aschcr- 
 sonia alcyrodis. and the yellow pigment of A. flat'o-citrina. 
 
 The growth on sweet potato plugs is given here for comparison with 
 the growth of Aschersonia flaVD-citrina on this same medium. 
 
 1. ( )n April <s. 1JM)?, spores were transferred from cultures made on 
 January 14, 1907. The spores were streaked onto the surface of the sweet 
 potato plug with a platinum needle. On April 17, abundant growth all 
 along the streak had begun. ( )n April 2(>, a large raised red mass, 40 mm. 
 long, had formed. 
 
 8. < )n April s. spores were transferred as in Xo. 1. On April 17, very 
 abundant growth had started, and on April 2(>, a very large red mass had 
 formed. 
 
 .">. ( )n April s. spores were transferred as in Xo. 1. On April 17, good 
 growth with thickened points had started. ( )n April 2<>. a very large mass 
 of red growth had formed. 
 
 I. ( >n April S. spores were transferred as in Xo. 1. On April 17. a 
 cream-colored to orange, mealy appearance was evident, spreading to each 
 side of the streak. ( )n April 2<>, an abundant growth, red in color, had 
 formed. 
 
 KXI'KKIMKNTS IN C.KOWI.XC. AsC 1 1 KKSo\ I A AI.KYRODI S IN I.AKC.I-. <J t 'A N TIT I I-S. 
 
 In April, r.ni;. experiments were begun in order to grow large quantities 
 of fungus for infection of Alc\rodcs citri. Ten large moist chambers, nine 
 wide-nKHlthed bottles of .V><> cc. capacity, and four petri dishes five inches 
 in diameter, wen.- prepared with sweet potato medium. The potatoes were 
 washed, peeled, washed again and put through a meat chopper. This 
 ground-up ma.ss was then washed in running water to get out tine particles. 
 and the moist medium was sterilized in the autoclave at 110 C. for about 
 20 minuu-s. After .sterili/ation. the medium appeared well cooked. 
 
 ( )n April '. these were inoculated, in the transfer closet, by spraying the 
 >urfaiv of the medium with a hand atoini/cr with a mixture of conidia in 
 
ASCHKRSONIA ALEYRODIS. 15 
 
 sterile water. The conidia were obtained from an old culture of the fungus 
 grown on sweet potato. All of the cultures, except two large petri dishes, 
 finally became contaminated with a growth of bacteria. This-was probably 
 due to insufficient sterilization of the interiors of the large masses of medium 
 : n the moist chambers and in the 500 cc. bottles. The fungus in the two 
 petri dishes which were successful, appeared in 15 days as a creamy white, 
 ieit-like growth over the surface of the medium, with no red color. Very 
 little red color appeared later, and no large spore-masses developed. It 
 seemed that the spores had been sown too thickly over the surface to develop 
 the characteristic pustules with pycnidial cavities. This experiment was 
 practically a failure. 
 
 On June 12, 1907, five bottles of ground-up sweet potato, and one bottle 
 of bread, which had been sterilized in an autoclave for about half an hour 
 at 120 C., were inoculated by streaking the surface with a large platinum 
 loop from cultures previously made on sweet potatoes. Three of these 
 were successful, two on sweet potato, and one on bread. The notes on 
 these are as follows : 
 
 1. On June 12, 1907, a culture on bread was made from a culture on 
 sweet potato plug, which had been transferred three times from an isolation 
 culture in petri dish poured December 7, 1906, and described above. 
 
 Transfers had been made on January 14, 1907, April 10, 1907, and June 
 3, 1907. On June 19, the fungus was growing well at one point. 
 
 On July 1, a large raised mass */2 inch in diameter was formed. On 
 July 20, a large area 1 inch in diameter, and red in the interior, with abund- 
 ant spores, had grown. 
 
 2. On June 12, 1907, a culture on sweet potato was made from another 
 culture with same history as above. On June 19, the fungus had started at 
 seven points. On July 1, masses 1-3 inch in diameter had formed on one 
 side of the bottle. 
 
 3. On June 12, 1907, a culture on sweet potato was made from a sweet 
 potato plug, which had been transferred once from a petri dish culture of 
 April 10, 1907, being transferred on June 3, 1907. On June 19, the fungus 
 was just starting at three points. On July 1, raised areas one inch in 
 diameter had formed on one side. On July 20, a growth l/ 2 inch in diam- 
 eter had formed. 
 
 ( )n June 19, six bottles of sweet potato and one of bread were inoculated 
 from sweet potato test-tube cultures which had been transferred twice from 
 an isolation culture made not later than April 10, 1907. Four bottles de- 
 veloped pure cultures. 
 
 1. On June 19, 1907, the surface of a bottle of sweet potato medium 
 was streaked with a small needle from a culture of June 3, 1907. On July 
 1, three or four areas of growth had appeared. On July 20, a good white 
 growth had formed all around the base of the potato plug. 
 
 2. On June 19, 1907, sweet potato medium was streaked as in No. 1, 
 from a culture made June 3, 1907. On July 1, a good growth had formed 
 on the surface, white and lumpy in appearance. On July 20, the growth had 
 formed all over the surface of potato, and spores had grown in the pycnidia. 
 On August 12, spores were very abundant. 
 
 3. On June 19, 1907, sweet potato medium was inoculated by shaking 
 up conidia in a test-tube of water and pouring it over the plug. On July 1, 
 very small areas on side of glass appeared. On August 12, areas of large 
 size had grown, but no conidia could be found. 
 
1C Kr.\<,l PARASITIC rroN A I.KYROl >KS ClTRI. 
 
 I. On I une 1!>, I'.HI;, bread medium was inoculated as the sweet potato 
 in No. :. with eonidia from a culture made on June :>, 1907. The old potato 
 plug from the same culture was also dropped in. ( )n July 1, a good growth 
 out from old plug had started. On July ><>. growth over nearly entire 
 surface, reddish in patches, had formed. On August 12, no eonidia could 
 l.e found. 
 
 INI-KCTION 01- AI.KYKODKS CITKI 1-ROM cn.Tl'KKS. 
 
 In two localities in the State, this fungus was started on larvae of 
 .-llcvrodcs citri, from cultures which had grown for some time on culture 
 media in the laboratory. This infection work was done by E. W. Berger 
 at Gainesville and St. Petersburg, from cultures grown by the author. 
 The following records are taken from E. \Y. Merger's field notes: 
 
 1. . \ugtist 1(). HOT. Gainesville. From culture on sweet potato made June :>:\. 
 having been isolated not later than April 10, 1907. Culture mixed up in water and 
 sprayed with hand sprayer on under surface of leaves on lower branches of an orange 
 tree. October 6, no fungus found. On Xovemher 1(>. three pustules of fungus found. 
 On December :M. sprinkling of pustules evident. April ::. 1!H)S. quite a sprinkling of 
 fungus pustules evident. 
 
 :.'. August 10. I'.ioT. Gainesville, Florida. From old cultures in three test-tubes. 
 Age of cultures unknown. No start by April :;. I'.ios. 
 
 ::. August 1.">, I'.ioT. St. Petersburg, Florida. From culture made June !'., on 
 bread in large bottles and transferred twice before from cultures isolated not later 
 than April 10. The culture was washed to fine pulp in water and strained. One and 
 a half to two quarts of the liquid was used. Sprayed on the under side of leaves with 
 a compressed-air sprayer. On October :'!!, quite a sprinkling of fungus was found. 
 Some twigs had several leaves well covered with pustules, mainly on the newest 
 growth. On December ](). about the same condition. On February 8, 190S, an abund- 
 ance of fungus was found on northwest side of tree, and fresh pustules were appearing. 
 
 t. August 1". I'.iOT. St. Petersburg, Florida. From culture on sweet potato, 
 made June 1'.i. I'.iOT. Culture washed to fine pulp and strained. Two quarts of solu- 
 tion were sprayed on with compressed-air hand sprayer. On October :Z3. a good 
 sprinkling of fungus was found with some leaves well covered. P>est catdi was on 
 we>t side, mainly on newer growth. On December 10, I'.IOT. pustules more mature. 
 but apparently not spreading. On February s I'.ios. an abundant catch of fungus was 
 evident. 
 
 5, August i:,. I'.MiT. St. Petersburg. Florida. From a mixture of two cultures, 
 one of Ascfarsonta alcyrndis made June I'.i on potato plug and transferred twice 
 before; the other of . Isi'licrsaiihi flai'o-citrina made May ::;. mi sweet potatoes in a 
 bottle, and transferred twice before. Cultures mixed, washed and strained, making 
 one gallon of the solution. On October '.':;, fair sprinkling of the fungus, probably 
 only the red. mainly on newer growth. ( )n December 10. same, but pustules more 
 matured On February 8, I'.-os. all red pustules, no yellow pre-uit. 
 
 <; August 14. I'.iOT. St. Petersburg. Florida. From culture made June I'.i. I'.iOT. 
 and transferred twi.-e before. \o start by February 8, 1908. 
 
 \ugust M. I'.iOT. St. Petersburg. Florida. From culture made April s. I'.HMi, 
 which had been dried for two months. The fungus bad been transferred twice' before. 
 Isolated from petri dish culture made December T. I'.ioi;. \o start of fungus by Feb- 
 ruarv .s. itMis. 
 
ASCHERSONIA FLAYO-CITRINA. 17 
 
 DISTRIBUTION OF ASCHERSONIA ALEYRODIS IN 1908. 
 
 In Florida it has been reported from or seen at the following places, 
 occurring only on Aleyrodcs citri: 
 
 Alva, Apopka, Bartow, Bradentown, Buckingham, Citra, Fort Myers, 
 Gainesville, Glen St. Mary, Jacksonville, Lake City, Leesburg, Manatee, 
 Mclntosh, New Smyrna, Oneco, Orlando, Oviedo, Palmetto, Sarasota, St. 
 Petersburg, St. Augustine. 
 
 Outside of Florida it was reported by Cook and Home from Cuba on 
 Aleyrodcs citri R. & H., and Aleyrodcs howardii. Quaintance ; from Java 
 by Kirkaldy & Kotinsky, doubtfully upon Aleyrodcs longicornis Zehntner; 
 from Brazil by the same authority, doubtfully upon Aleyrodcs horridus 
 Hempel; from Ceylon by Parkin on various undetermined species of Aley- 
 rodes; and from Jamaica by Cockerell under the name of Aschcrsonia tahit- 
 ensis Mont., which is probably A. alcyrodis Webber. 
 
 III. ASCHERSONIA FLAVO-CITRINA P. HENN. 
 
 The discovery that Aschcrsonia flai'o-citrina P. Henn. was parasitic 
 upon Aleyrodcs citri R. & H., was made by P. H. Rolfs 25 by means of 
 specimens sent to him from J. F. Adams, Winter Park, Fla., in September, 
 1906 (Plate II, Fig. 24). Later in the same year E. W. Berger found this 
 fungus effectively parasitizing Aleyrodcs citri in several other localities in 
 the eastern part of Florida, and since that time he has succeeded in intro- 
 ducing it into still other localities. This fungus was first described by P. 
 Hennings in 1902, as occurring on leaves of Psidium from the botanical 
 gardens of Sao Paulo, Brazil. No mention is made by him of any insect 
 associated with its presence on the guava leaf. This species is described by 
 Hennings 26 as follows : 
 
 Aschcrsonia flai'o-citrina P. Henn. Stromatibus carnosis, hypophyllis, subdis- 
 coideo-pulvinatis vel hemisphaerico-depressis, citrinis, 2 2.5 mm. diameter, pruinosis, 
 superne ptmctulato-pertusis, intus subaurantiis, subiculo membranaceo, flavo ; pycnidiis 
 immersis oblongis, paraphysibus filiformibus, flexuosis, hyalinis 140-180X11.5 micr., 
 continuis; conidiis fusoideis, utrinque acutis, continuis, hyalinis, 12-18X2 micr.; con- 
 idiopboris brevibus, hyalinis, fasciculatis. 
 
 It was found in the botanical garden of Sao Paulo on a leaf of Psidium 
 sp., October, 1901. 
 
 That Aschcrsonia flai'o-citrina may be able to attack other Aleyrodidae 
 besides A. citri is shown by the fact that in June, 1907, Stene of the Rhode 
 Island College of Agriculture, was able to infect larvae of Aleyrodcs raf>or- 
 arionnn, on cucumber leaves in the greenhouse, from material sent from 
 Florida by E. W. Berger. 27 These are the only two species of Aleyrodes on 
 which it has yet been observed. It is probable, however, that further ob- 
 
 25 Rolfs, P. H. Fla. Exp. Sta. Kept., p. xvi, 1907. 
 'Hennings. P. Hedwigia, Vol. 41, p. HOT, 1902. 
 21 Berger, E. W. Fla. Agr. Exp. Sta. Kept., p. xxxiv, 1907. 
 
18 FUNGI PARASITIC UPON AI.EYRODES CITRI. 
 
 servations will reveal its presence on other Aleyrodidae native to the woods 
 of Florida. 
 
 COMPARISON OF ASCHERSONIA FLAVO-CITRINA WITH A. ALEYRODIS. 
 
 The two species are very much alike in their general appearance, and 
 also approach each other closely in the measurements of their structural 
 parts. The most evident distinction is in the color. A. aleyrodis is usually 
 red or pink, while A. flavo-citrina is yellow and never contains any reddish 
 pigment. The stromata of A. aleyrodis, under similar conditions, average 
 less in diameter, and the pycnidial cavities are usually more sunken than 
 in A. flavo-citrina. The spores of A. aleyrodis also average a little smaller 
 than those of A. flavo-citrina. Measurements of Florida specimens show 
 that the spores of A. aleyrodis are about 9 14X2 3 microns, while those 
 of A. flavo-citrina measure about 12 15X2 3 microns. Cultures of these 
 two Aschersonias on similar culture media, under similar conditions, showed 
 them to be distinct forms. 
 
 CULTURES. 
 
 Soon after the discovery of A. flavo-citrina on Aleyrodcs citri, attempts 
 were made by the writer to produce cultures of this fungus on ordinary 
 culture media. Attempts to isolate Aschersonia aleyrodis on neutral pep- 
 tonized agar had been made without success. The beneficial effect of the 
 addition of sugar on the germination of the spores in hanging drops had 
 been noticed. On the addition of 10 per cent, glucose to the agar, petri dish 
 cultures of A. flavo-citrina were successfully grown. The growth on 10 
 per cent, glucose agar, poured on September 14, 190f>, at a temperature of 
 about 28 to 30 C., was as follows: 
 
 On October 2 (18 days) small, whitish delicate-fringed colonies ap- 
 peared, just visible to the unaided eye. On October 11 (25 days), a distinct 
 elevated stroma had formed, waxy and pale, with a yellow center contain- 
 ing pycnidia with spores. Surrounding this was a white fringe of outgrow- 
 ing mycelium. These stromata became 2 to (> millimeters in diameter, and 
 closely resembled the stromata growing naturally on leaves bearing larvae 
 (Plate III, Fig. 2G). Later cultures grown on the same medium bore 
 stromata 2~> millimeters in diameter, indicating that the size of any individual 
 stroma depends on the amount of the medium taken, and the length of time 
 before it is dried out (Plate III, Fig. 27). The fungus was then transferred 
 to test-tubes containing other media. Cultures were obtained on sterilized 
 SWeel potato. Irish potato, hread and Her. The most luxuriant growth was 
 obtained on sweet potato plugs, this being probably due to the presence of 
 BUgar in that medium ( I 'late IV. Figs. 88, -.".' and 30). 
 
 The progress of the fungus on the various media was as follows: 
 On sweet potato pings, transferred from petri dish culture by inserting a 
 platinum needle into a spore mass, tin-re was no evident growth in three 
 days. In six days, numerous small white points appeared along the scratch 
 made- by the needle. In fourteen days, stromata > mm. in diameter, and 
 turning yellow, were formed. In twenty days these had heroine typical 
 
ASCHERSONIA FLAVO-ClTRINA. 19 
 
 stromata with spores. In forty-seven days, these separate points had grown 
 together into one waxy, yellow mass, fringed and tipped with a white 
 velvety growth of vegetative hyphae, as shown in the photograph (Plate IV, 
 Figs. 28, 29, 30). Numerous pycnidial masses were also present. On 
 Irish potato plugs, the growth of the fungus, for the first fourteen days, 
 was about the same as on sweet potato plugs. From that time on, the 
 growth was more feeble, and the yellow color rarely 
 appeared. Typical spore-masses were not so abund- 
 ant. On sterilized rice there appeared in ten days a 
 slightly yellow growth, not much raised above the 
 surface. In eighteen days, the growth had spread 
 out considerably over the surface of the rice, and the 
 color had become a decided yellow, without present- 
 ing any raised mass as described for sweet and Irish 
 potatoes. In thirty-four days, there appeared small 
 whitish patches over the surface of the yellow 
 growth. On white cornmeal, the growth of the 
 Fig. 5. fungus was the same as on rice. On bread, the 
 
 Hyphae ofjtroma. fungus grew well and formed yellowish masses in 
 a few weeks. 
 
 GERMINATION OF CONIDIA. 
 
 The germination of the conidia of this fungus was very 
 slow as compared with that of many fungi. In September, 
 190(3, germination tests were made of conidia placed in 
 hanging drops of distilled water, tap water, agar, and 
 various solutions of glucose in water. These were pre- 
 
 i 1 1 r f i Fig. 6. Conidia from 
 
 pared by placing a number of minute drops of the solution dried pustules of 
 
 . , . , . Aschersonia flavo- 
 
 on each sterilized cover glass, and putting in them by atrina, x 1000. 
 means of a sterile needle a few conidia from fresh pustules of the fungus. 
 These were then placed in a moist chamber to keep them from drying out. 
 In all of these solutions some germination took place. In distilled water and 
 tap water, the germination was slow and feeble, the hyphal tube not advanc- 
 ing far. The addition of sugar appeared to increase germination up to 10 
 per cent, of sugar. Above 10 per cent, germination was retarded, and at 30 
 per cent, only a few spores were seen to germinate. In October, 1907, part 
 of the same test was repeated with the same general results ; except that in 
 this case the conidia in 5 per cent, glucose solution appeared to germinate 
 a little more readily than in 10 per cent, and the conidia in 30 per cent, solu- 
 tion refused to germinate at all. Parallel tests in part were made with 
 conidia of Aschersonia aleyrodis with similar results. 
 
 The table below gives the result of the tests for Aschersonia flavo-citrina. 
 In germinating, the first hyphal tube usually pushed out just behind one of 
 the acute ends of the boat-shaped spore (Figs. 7, 8 and 9). The acute end, 
 
l-TNC.I I'.'.RASITIC ri'ON AI.KYRODES CITRI. 
 
 which seemed to lack protoplasm, was bent back in the opposite direction. 
 
 The hyphal tube then grew very slowly, 
 and in four days, in 10 per cent, glu- 
 cose solution, began to form sporids 
 at the distal ends (Figs. 8 and 9). 
 
 Fig. 7. ronidium of A*rhi'i:*ni<i ,/fmo-cftrftM 
 germinal 'ng in ::o per cent glucose solution 
 after 27 dats. (a) Original conidium, (!>} 
 spore like bodies. X 1000. 
 
 Fig. 8. Fig. 9. 
 
 Figs. 8-9. Conidia germinating, (n) conidium. (b) 
 hyphal tube, (c) sporid, X 1000. 
 
 ASCHERSOXIA FLAYO-CITRINA GERMINATION OF CONIDIA. 
 
 MEDIUM. 
 
 '.' I TO 28 HOURS. 
 
 44 TO 48 HOURS. 
 
 
 Distilled water.. . 
 
 No germination. 
 
 Germination just be- 
 ginning. 
 
 
 Tap water .... 
 
 X> germination. 
 
 Germination just be- 
 
 In 6 days good germ- 
 ination, some hyphae 
 
 
 
 ginning. 
 
 2 or 3 times longer 
 than the conidia. 
 
 Glucose 1 per cent. 
 
 Germination just be- 
 ginning. 
 
 Fairly good germina- 
 tion. 
 
 
 Glucose 2 per cent. 
 
 Germination just be- 
 ginning. 
 
 .(Dried out.) 
 
 
 Glucose 3 per cent. 
 
 Germination advanced 
 farther than in 2 per 
 
 Very good germination 
 of many conidia. 
 
 
 Glucose 5 per cent Good germination in :>* 
 hours, hyphal tubes as 
 long as conidia. 
 
 Good germination, hy- 
 phae growing slowly. 
 
 
 GlucoM- in per cent. 
 
 Very good germination, 
 hyphal tubes 2 to 3 times 
 length of conidia. 
 
 Very good germination, 
 hyphae growing slowly. 
 
 In 4 days sporids form- 
 ing on ends of hyphal 
 tubes. 
 
 Glucose 20 per cent. 
 
 Only a few just begin- 
 ning to germinate. 
 
 1 lyphal tubes as long as 
 conidia. 
 
 
 GlucnM- :;n ,,,-r rent. 
 
 No germination. 
 
 No germination. 
 
 A very few finally 
 germinated. S p o r ids 
 formed in 27 days. 
 
 ( M-rminatinn tests of conidia fn.ni dried pustules made at various times 
 showed the following results: 
 
 1. ( )n November 1". iwii. lian^in^ drop cultures were made from 
 specimens sent in from Winter I 'ark on September -'S, 1 !HX;, which had 
 remained in the laboratory exposed to the atmosphere for 1C. (lavs. Tests 
 
VKRTICILUUM HETEROCIvADUM. 21 
 
 were made in distilled water, in tap water and in 5 per cent, glucose at a 
 temperature of 15 to 20 C. No germination occurred up to December 
 11, 1906, when the slides were discarded. 
 
 '2. On January 5, 1907, hanging drop cultures of conidia in distilled 
 water were made from leaves picked September 28, 1906, which had re- 
 mained in the laboratory exposed to the atmosphere for 68 days. No germ- 
 ination was noticed up to January 9, 1907, when the slides were discarded. 
 
 3. On January 5, 1907, hanging drop cultures in tap water were made 
 from leaves collected by E. W. Berger on December 18, 1906, and kept in 
 the laboratory 18 days. On January 7, many conidia had germinated, and 
 on January I), some hyphal tubes were twice as long as the conidia. 
 
 4. ( )n April 18, hanging drop cultures were made from leaves collected 
 on September 28, 1906, at Orlando, and kept in the laboratory 203 days. 
 No germination had occurred by April 29, 1907, when the slides were dis- 
 carded. 
 
 A SUPER-PARASITIC OF ASCHERSONIA FLAYO-ClTRINA. 
 
 A super-parasite belonging to the genus Cladosporium has been noticed 
 as of common occurrence on Aschcrsonia flaio-citrina. Attention was first 
 called to it by A. W. Morrill, who afterwards observed it at Orlando over- 
 running this Aschersonia, in the summer of 1906. Later on a brief report 
 was given by E. W. Berger. Plate VII, Fig. 4.3, shows a leaf from Or- 
 lando with pustules of Aschcrsonia flavo-citrina covered over with the 
 dark brown Cladosporium. This same fungus has also been observed by 
 the writer associated with sooty mold (Meliola) in secretions of honeydew 
 from Alcyrodes citri, and it appears to aid at times in smothering the white- 
 fly larvae, as does also the Meliola. Cultures of this fungus were readily 
 obtained in 5 per cent, glucose agar, and the fungus was transferred to 
 potato plugs. The growth was rapid and the color was the same as on 
 the leaves. 
 
 DISTRIBUTION OF ASCHKRSONIA Kr.AYO-ClTRINA IN FLORIDA IN 1908'. 
 
 Altamonte Springs, 
 
 Gainesville (introduced) , 
 
 Largo (introduced), 
 
 Maithmd, 
 
 New Smyrna (introduced), 
 
 ( )rlando, 
 
 Oviedo, 
 
 St. Petersburg (introduced), 
 
 Winter Park. 
 
 IV. YERTICILLIUM HETEROCLADUM PENZ. 
 
 The attention of the writer was first called to this fungus in November, 
 1!)()5, b\ E. H. Sellards, Entomologist of the Florida Experiment Station, 
 who brought in specimens of Brown fungus from Palmetto, Florida, with 
 which was associated a cinnamon-colored fungus. At the time of its dis- 
 
FUXC.I I'.'KASITIC UPON ALEYRODES CITRI. 
 
 coveiv on .-llcyrodcs citri, it was thought that this fungus might possibly 
 be the spore-bearing stage of the sterile "Brown fungus" described by 
 Webber, because of its close association with the stroma of the Brown 
 fungus, and since it also resembled the Brown fungus somewhat in color. 
 Cultures of the I'crticUlium hctcrochuium, however, together with inocula- 
 tions oi larvae of Aleyrodcs citri in the greenhouse, showed that this fungus 
 was distinct from the Brown fungus found by Webber in 1890. Further 
 evidence of its distinct character was subsequently obtained when it was 
 found in other localities on Aleyrodcs citri and on other insects, in no way 
 associated with the Brown fungus. At Palmetto, where it was first dis- 
 covered, it was seen to be attacking the long scale, Mytilaspis citric ola, that 
 occurred on the same leaves with larvae of Aleyrodcs citri. In 1907 it was 
 found on Mytilaspis glorcrii at Gainesville, quite independent of the Brown 
 fungus. During the same year, it was found on a species of Diaspis on the 
 leaves of Euonymus Amcricanns in the woods near Gainesville. Later on 
 it was observed unaccompanied by Brown fungus on Aleyrodcs citri at St. 
 Petersburg, Fla. It was introduced by the writer on larvae of Aleyrodes 
 citri on a privet hedge at Gainesville in the fall of 1907. It was also intro- 
 duced by Mr. Gaitskill along with the Brown fungus on larvae of Alevrodes 
 citri at Mclntosh, during the summer of 1907. Specimens of the same 
 fungus on Aleyrodes citri were sent in from Apopka and Citra, Florida, 
 early in 1908. In a few cases only has it been found in large quantities, 
 and as yet its efficiency as a parasite of Aleyrodes citri is not fully de- 
 termined. In its parasitism it differs from the three fungi previously de- 
 scribed, by attacking other insects not belonging to the genus Aleyrodes. 
 Several other species of the genus Verticillium have been reported as 
 occurring on insects. 1'crlicilliiim aphidis Bauml. 28 on plant lice, and Verti- 
 cillium minutissimum Corda 29 on larvae of a small insect, were described 
 from Europe. An undetermined species of Verticillium is reported by J. 
 Parkin 30 on a scale insect Asterolccanium miliaris which was infesting the 
 leaves of a bamboo bush in Ceylon. Parkin also refers to Gueguen as 
 authority for the statement that 1'crticiUium hctcrochuium had been found 
 in Africa and the Antilles. It would therefore appear to be a widely 
 distributed species. 
 
 DESCRIPTION. 
 
 This fungus was first described and figured by O. Penzig/ 51 in 1882, 
 occurring on Lecanium hcsperidum on lemon leaves in Italy. His descrip- 
 tion is as follows: 
 
 /'// /V/7/iMwi hctcrocladum Penzig (Fung. Agrumic. N. 108, Fig. 1193). Hyphis 
 
 * Saccardo, P. A. Sylloge Fungorum, X, p. 546, 1892. 
 
 9 Ibid. IV. p. 152, 1886. 
 
 '"Annuls Roy. Bot. Card., Peradeniya, Vol. Ill, Part T, p. }.", 1906. 
 
 <ii I'.otanici sugle Agrumi c sullc Planti Aflini, p. 398, Tavola XU Fig 3 Roma 
 1887. 
 
VERTICIUJUM HF/TEROCLADUM. 
 
 23 
 
 repentibus, elongatis, paulltim ramosis, continuis; ramis fertilibus adscendentibus, 
 ramnlosis ; ramulis ternis vel quaternis, oppositis vel alternis, patentibus, rectis, apice 
 attenuatis ; conidiis in ramulorum apice solitariis, geminatis vel ternis, saepius pedi- 
 cellis brevissimis stiff ultis, oblongis, hyalinis, 5.5-6 micr. long., 2-3 micrTcfassis. 
 
 Verticillium heterocladum, in general 
 appearance, resembles the Brown fungus 
 of Webber (Plate IV, Fig. 31). On close 
 examination, however, it is found to be 
 strikingly different. The pustules, which 
 are cinnamon colored, are powdery on 
 the surface. Under the hand lens, they ap- 
 pear brushlike in form, bristling with 
 hyphae. From the edge of the pustules 
 there grows out a creeping layer of white, 
 delicate, interwoven hyphae. From these 
 colorless hyphae, as well as from the top 
 of the pustules, there arise upright con- 
 idiophores. These may have eithet a 
 simple series of whorls, 2 to 4 branches 
 in each, or the branches of the whorls 
 may again be whorled. The conidia are 
 borne on the ends of the ultimate 
 branches (Fig. 10). 
 
 The conidiophores are quite delicate, 
 slender, hyaline, 150 to 240 microns by 
 times septate. The conidia are oblong, hyaline, 
 The main body of the cinnamon- 
 in 
 
 Fig. 10. Verticillium hetei-ocladum. () Conidio- 
 phore with conidia forming, X 450. (b) 
 Conidiophorewith mature conidia. X 450. 
 (c) Conidia, X 1000. 
 
 o to 4 microns, several 
 4 to 6 microns long by 1.5 to 2.5 thick, 
 colored stroma when mature becomes powdery 
 appearance, and under the microscope it is found 
 that the hyphae have broken up into short pieces 
 irregular in shape and length with rounded ends, 
 some of them quite closely imitating spores (Fig. 
 11). These have thicker walls than the conidia, 
 and probably act as reproductive bodies in carry- 
 ing the fungus through a period of dry weather. 
 
 Fig. 11. Short hyphal bodies 
 into which the central por- 
 tion of a mature pustule 
 breaks up, X 450. 
 
 CULTURES. 
 
 Pure cultures of this fungus were made in November, 1905, soon after 
 the fungus was discovered on Aleyrodes citri. The next year other cultures 
 were made and spores of the fungus transferred from cultures to larvae 
 of Aleyrodes citri in the greenhouse. The fungus was readily grown in 5 
 per cent, glucose agar by drawing a moistened platinum needle over the 
 top of the upright conidiophores and then washing it off into the melted 
 agar. 
 
 On November 12, 1906, two petri dishes (A and B) of 5 per cent, glu- 
 
21 l-r.\(,i I'AKASITIC UPON ALEYRODES CITRI. 
 
 cose agar were poured. A moistened needle was drawn over the upright 
 brush of conidiophores and washed into a little bouillon in a test-tube. In- 
 oculations were made from this with a platinum loop, nine loops being 
 transferred to A, and nine from A to B. 
 
 On November 20 (8 days), 120 pure white mycelia appeared in A and 4 
 in 1>. :> to 4 mm. in diameter, with reddish brown center and a brush of up- 
 ward growing white conidiophores. On December 5 (23 days), the mycelia 
 in B were 25 mm. in diameter and reddish brown. On December 12 (32 
 days), the mycelia in B were 30 to 35 mm., and cinnamon-colored almost 
 to the edges. By this time a pustule was formed composed of closely inter- 
 woven hyphae and closely resembling the pustules upon larvae of Ale\rodes 
 citri (Plate V, Fig. 34)." 
 
 The fungus was transferred to test-tubes of sterilized Irish potato, 
 sweet potato, rice, white cornmeal, stems of canna and of caladium, and 
 bread ; on all of which the fungus grew to some extent. It grew best, how- 
 ever, on sweet potato and bread, over the entire surface of which it formed 
 a felted cinnamon-colored stroma (Plate V, Figs, 32, 33). On rice the 
 color was that of ocher, and on caladium stems it was brick-red. On the 
 other media the color was nearly that of the growth on 5 per cent, glucose 
 agar. 
 
 The growth on sweet potato plugs was recorded as follows : On Novem- 
 ber 22. 1 !><<;, conidia from cultures made November 12, were rubbed on the 
 surface of the potato. On December 5 (13 days), a brown colored growth 
 had formed over the surface of potato. By December 12 (20 days), the 
 entire surface was yellowish brown. On January 15, 1907 (39 days), the 
 entire surface was covered over with a thick cinnamon-colored mat of 
 fungus. 
 
 (.KR MI. NATION OF CONIDIA. 
 
 Conidia were placed in distilled water in hanging drops. It was found 
 that they germinated much more rapidly than did the conidia of Ascher- 
 sonia. In distilled water, in 24 hours, conidia had just begun to elongate; 
 in 18 hours a few spores were found with short hyphal tubes. In bouillon, 
 in 24 hours a slight germination took place, the hyphal tubes becoming as 
 long as the spore: in :> days, the hyphae were 120 to 200 microns long and 
 1 to \ l /2 microns wide, and branched once or twice. 
 
 In ~> per cent, glucose, in 24 hours, the tube had extended one to two 
 times the length of the spore, and in three days, the growth had proceeded 
 farther than those in distilled water. 
 
 When germinating, the spores first swelled, elongated, and then sent out 
 a hyphal tube from one or both ends. 
 
 IM IATION OF LARVAE OF ALEYRODES CITRI. 
 
 ( )n December (\, llinii. small badly infested orange trees which had pre- 
 viously been in the greenhouse, were covered wiih large belljars. Conidia 
 from a petri dish culture poured Xovember 12, I'.MM; \->\ days old), were 
 shaken up in sterile water, and this was spraved on to the plants with a 
 small atomizer. In :>:> days several leaves were found with stromata in a 
 spore-bearing condition, identical with those from which the culture had 
 originally been obtained. These had evidently developed sooner than 35 
 lays, and had been overlooked. Thev became powdery in appearance and 
 in all particulars were like the natural pustules. 
 
SPHAEROSTILBE COCCOPHIIA. 
 
 On September 19, 1907, leaves containing VerticiUiuni hctcrocladum 
 were tied to a twig of privet (Lignstrnm ovalifolium) bearing abundant 
 larvae of Alc\rodcs citri. The weather was moist for two weeks^ after. 
 
 On October 5 (16 days), pustules were very evident on inany larvae 
 on leaves adjacent to those tied in. Under the microscope a mycelium was 
 to be seen inside the larvae. On October 25 (36 days), the fungus with 
 conidia was well established on a few neighboring leaves, but was not 
 spreading rapidly (Plate V, Fig. 35). 
 
 On November 16, leaves of Enonymns Ainericanus bearing a species 
 of Diaspis attacked by Verticillium hctcrocladum were pinned on to an 
 orange tree at Gainesville by E. W. Berger. On December 31, 1907, three 
 pustules of freshly grown Verticillium were found (one on a scale insect, 
 probably Lecanium, and the others apparently on larvae of Aleyrodcs citri),. 
 on a tree next to the one in which the fungus had been pinned. 
 
 INSECTS PARASITIZED, WITH LOCALITIES. 
 
 Aleyrodcs citri: Palmetto, Manatee, St. Petersburg, Gainesville, Apopka, 
 Citra, Mclntosh. 
 
 Mytilaspis ghverii : Gainesville. 
 
 Diaspis sp. on leaves of Buonyimis Ainericanus \ Gainesville. 
 
 Lecanium sp. on orange leaves: Gainesville. 
 
 Lecanium hcspcridnm on lemon leaves: Italy. 
 
 Mytilaspis citricola: Palmetto, Citra. 
 
 In Africa and the Antilles the host insect is not known. 
 
 V. SPHAEROSTILRE COCCOPHILA TUL. 
 
 This fungus, which has a world-wide distribution, and has been re- 
 ported as a parasite on no less than fifteen different species of scale insects, 
 has been found in a few instances attacking larvae of Aleyrodcs citri. 
 
 The conidial stage of this fungus (Figs. 14 
 and 15) was discovered by Desmazieres :}2 on 
 
 scales of a coccid on young willow-stems in 
 France, as early as 1848. It was described un- 
 der the name Microccra coccophiia. The per- 
 ithecia (Figs. 12 and 13) were discovered by 
 
 Tulasne 33 and described by him in 1865 as oc- 
 curring on scale insects on species of Laurus, 
 
 Salix and Fraxinus in France, Italy and Amer- A Fig : f ly> 
 
 A 
 
 X75. 1D! ica - Desmazieres' description is as follows: Ci ^ rit x h 2 e oo 
 
 Microccra, Desmaz. Velum externum persistens, membranaceo-floccostim, dein 
 
 supra in lacinias plures rumpens ; receptaculum clavatum carnosttm e fibris sub- 
 
 simplicibus sporidiiferis formatum ; sporidia fusiformia, acuata. 
 
 Microcera coccophiia Desmaz. M. minutissima, subcaespitosa cornuto-conica, 
 
 simplex, lateritio-rosea, basi membrana tenuissima albida vaginato-connata. Sporidiis- 
 
 paucis, hyalinis, elongatis, utrinque acutis. Hab. in coccis. Hieme. 
 
 " Desmazieres. Ann. des Sc. Nat., Tome X, p. 359, 1848. 
 Tulasne. Carpologia, Vol. Ill, 105, 1865. 
 
26 FUNC.I PARASITIC UPON ALEYRODES CITRI. 
 
 The ascus stage is described in Saccardo's Sylloge Fungorum 34 thus : 
 Sphacrostilbc coccophila Tul. Carp. III., 105. Peritheciis permultis supra et prope 
 stromata conidiophora nascentibus, minimis globosis, obtusis, brevissime papillatis, 
 glaberrimis, nitide rubris, saepe 4-5 sociatis, senio collabentibus; ascis linearibus, 
 60-80X6J/2; sporidiis oblique monostichis, ovatis, 10X5, 1-septatis, subhyalinis, leniter 
 constrictis. Stat. conid. Microccra coccophila Desm. Stromate e crusta coccornm 
 solitarie oriundo, crasse teretiusculo, obtuso. rnbro 2 mill, alt.; conidiis lineari- 
 lanceolatis 4-6 locularibus, 65X6 subhyalinis. 
 
 In 1892, Ellis and Everhart-' 55 in "Xorth American Pyrenomycetes" gave 
 nearly the same description in English, and reported this fungus on a speci- 
 men of Alnus scrrulata collected in Pennsylvania, adding: 
 
 The conidial stage (Microccra coccophila Dcsm.) which has been sent from 
 Florida by Dr. Martin and collected in Carolina by Ravenel (F. Am. 286), has stroma 
 arising from various species of dead bark-lice. It is red, obtuse and about 2 mm. 
 high. The conidia are linear lanceolate, 5-7 septate and 56-65X5-6 microns, nearly 
 hyaline. 
 
 D. McAlpine 36 in describing the con- 
 /ft'''Vf\ idial stage of this species in Australia 
 
 /i la 1ft gives the measurements of the conidia 
 
 as 75103X5^8^ microns. Meas- 
 urements made of a number of Florida 
 specimens from different localities gave 
 
 Fig. 15. Conidia. 
 
 70112X3.56 microns. Measurements x 200. 
 of the perfect stage from Florida specimens were as 
 follows: Perithecia 350 390 long by 300 microns 
 thick. Divisions of perithecial wall 6 10 microns. 
 Asci, 7098X812 microns. Spores 1218X79 
 microns. 
 
 HISTORY. 
 
 !'!_'. 11. >i>orodochinm, or 
 
 *2K2S2S^ f This fungus has been found in nearly every coun- 
 try in the world. In 1892, M. C. Cooke 37 spoke of it 
 as common in Europe and as a well-known parasite on dead Coccus. In 
 the same year it was reported from Jamaica by T. D. A. Cockerell. 38 In 
 1894, Henry Tryon 39 reported it on the long scale, the red scale and the 
 circular black scale in Queensland, Australia. In 1897, it was reported 
 by P. H. Rolfs 40 as a parasite of the San Jose Scale, Aspidiotns pcrniciosus 
 Comst In 1899, it was reported by I). McAlpine 41 on Aspidiotns anrantii 
 
 **Saccardo. Sylloge Fungorum, II. p. :.!.;. 1S83. 
 
 Ellis, J. B. and Everhart, .M. I'.. North Aim-rioau Pyrenomycetes, p. 111. ]si:.'. 
 "Fungus diseases of Citric Tn-rs in Australia. Drpt. of Agr., Victoria, p. 113, 1899. 
 "Vegetable Wasps and Plant Worm-, p. :;:J:j. I.i>r.<l<m, 1S92. 
 "*Bul. Botanical Dept. of Jamaica, No. :;'.. p. r, i 
 "Queensland Dept. of Agr., Hul. l. p. i.v 
 "A Disease of San Jose Scale, Fla. Exp. Sta. Bui. 41. 
 
 41 Fungus Diseases of Citrus Tn-i-s in Australia. Drpt. of Agr., Queensland, np 27 and 
 28, 1899. 
 
SPHAEROSTILBE COCCOPHILA. 27 
 
 Mask, in Australia. In 1900, P. H. Rolfs 42 reported that Mytilaspis citri- 
 cola Pack., Mytilaspis gloverii Pack., and Parlatoria pergandii Comst. were 
 all attacked by this fungus in Florida. The same year F. B.~ iBafle 43 found 
 it common on Aspidiotus ob scums Comst. on water oaks in Alabama. It 
 also occurs naturally in Georgia, and has been found as far north as Phila- 
 delphia, Pa. In 1901, Fuller 44 reported finding the same fungus in Natal, 
 South Africa. In 1903, H. A. Gossard 45 first reported its occurrence on Al- 
 eyrodes citri. In 1903, F. S. Earle 46 found it in Porto Rico, and in 1904 47 
 in Cuba ; in both places on Mytilaspis citricola. In 1904, S. I. Kuwana 48 
 reported the fungus as present upon Aspidiotus peruiciosus Comst. and on 
 Diaspis pcntagona Targ. in Japan. He spoke of finding it on the last- 
 named insect in the mountain districts. In 1906, it was reported by J. 
 Parkin 49 as occurring upon Mytilaspis citricola Pack, and Aspidiotus aur- 
 autii Mask, in Ceylon. In 1908, it was reported by C. W. Howard 50 from 
 the Transvaal. It has also been found by E. W. Berger on Aspidiotus 
 hcdcrac (Vail) and Aspidiotus ancylus Putnam, in Florida. 
 
 Both the conidial and ascus stage of this fungus (Plate VI, Figs. 36, 
 37, 38) are found commonly in Florida, although the latter is not at all 
 common in other parts of the world. In Ceylon, the perithecia have not 
 been found by Parkin ; and one would infer, from the name Microcera, 
 which is used by D. McAlpine, that the perfect stage is not common in 
 Australia. 
 
 RELATION OF S. COCCOPHILA TO THE} SAN JOSE AND OTHER SCAI^E INSECTS. 
 
 The use of this fungus as a practical remedy in combating the San Jose 
 scale was first brought out by P. H. Rolfs in 1897, in Bulletin 41 of the 
 Florida Experiment Station. This fungus was discovered by him upon the 
 San Jose scale in northern Florida during the previous year. By means of 
 pure cultures and infection experiments, Rolfs demonstrated that the San 
 Jose scale could be readily infected with spores of this fungus grown upon 
 sterilized bread or other media. The results of these experiments are given 
 in the bulletin referred to. 
 
 This fungus was also discovered to be a common parasite of the obscure 
 scale, Aspidiotus obscurus Comst., on the twigs of water oaks (Quercus 
 aquatica). A simple method of infection has been developed in Florida by 
 one of the peach-growers, Mr. F. P. Henderson, by tying into the top of 
 
 42 Proc. Fla. Sta. Hort. Soc.. p. 63, 1900. 
 
 43 Ala. Exp. Sta. Bui. 106, p. 198, 1900. 
 
 4 " First Rept. of Govt. Entomologist, Dept. of Agr., Natal, p. 99, 1901. 
 
 43 Fla. Exp. Sta. Bui. 67, p. 623, 1903. 
 
 * Annual Rept. Office of Exp. Sta., Washington, D. C., p. 457, 1903. 
 
 4T Primer Informe Annual de la Estacion Central Agronomica de Cuba (1904-05), 
 
 p. 162, 1906. 
 
 48 Japan Imperial Agr. Exp. Sta. Rept., p. 26, 1904. 
 10 Annals Roy. Bot. Card., Peradeniya. Vol. Ill, Part I, p. 50. 
 50 Dept. of Agr., Transvaal, Agr. Journal, p. 6, 1908. 
 
l-T.M.I PARASITIC l'P().\ A I.K YK< >I>KS CITRI. 
 
 an 'nfested tree a short piece of .wood whose bark bears a good supply of 
 the fungus. This has proved to be a very effective way of distributing this 
 fungus, and has already saved thousands of dollars to the peach and orange 
 growers of the State. In addition to attacking Aspidiotns perniciosus and 
 . Ispidiotus ohscurus, this fungus is effective in checking a number of other 
 scale insects in Florida. It is, under favorable moisture conditions, an 
 effectual parasite of Mytilaspis citricola, Mytilaspis gloi'erii, Aspidiotus 
 ficus, .Ispidiotirs hciicrac and Parlatoria pergandii. There are times, in dry 
 weather, when these scale insects get ahead of the fungus ; but a moist 
 period of a few days will quite often enable the fungus ro kill them off 
 almost completely. (Plate VI, Figs. 3(5, 37 and 38.) 
 
 The effective work of this fungus, and two others, Ophionectria coc- 
 cicola E. & E.. and Myriangwm dttriaei Mont, upon the orange scales, is 
 readily shown by spraying an orange tree very thoroughly with Bordeaux 
 mixture. During the summer and fall of 1907, the author sprayed a num- 
 ber of orange trees with Bordeaux mixture for another purpose. The trees 
 were sprayed very thoroughly, once in May, once in July, and once in 
 September. Before the first spraying, the trees were practically unhurt by 
 Mytihispis citricola, only a few individuals of this scale being found on any 
 part of the trees. After the first spraying this scale insect began to spread, 
 and increased slowly in numbers until November, when the trees were badly 
 attacked by the scale. Other trees near by, that had received no spray, were 
 as free from scale as at the first. The fungicide had evidently destroyed, 
 on the sprayed trees, the fungi that had been all along working upon the 
 unspraved trees. 
 
 Soon after the discover}- of this fungus in Florida by P. H. Rolfs, ex- 
 periments were made by S. A. Forbes 51 of the Illinois Experiment Station, 
 Ii. Smith-" 1 - of the Xe\v Jersey Experiment Station, J. Craig 5 -' 5 of the 
 Canadian Experiment Station, and F. A I. Webster"' 1 of the Ohio Experi- 
 ment Station, to introduce Sphacrostilbc coccophila on San Jose scale in 
 the Xorth. hut the climate of these States did not prove to be conducive 
 to its spread, and the work was abandoned. 
 
 I'll II, A AS A PA HAS IT K o|- AI.I-VK )1)|-S CITKI. 
 
 As was stated previously. Spluicrostilhc coccophila seems to have been 
 first reported as parasitic on .llcyrodcs citri in 1!M)3 by H. A. Gossard. It 
 was f<und on larvae of .llcymdcs citri on orange leaves received from Or- 
 lando. In 1!Hi:,. K. II. Sellanls" 1 " 1 al.so reported having received it from 
 
 " 111. Kxp. Sta. I'.ul. :,('.. pp. 270 280 
 
 J. Kxp St.-.. Kept, is. ,, p . IT., 179, 1897. Kept. P.I. pp. 145-446. l.s'.is. Rept 24 n 
 
 "Canada Kxp. I-V.nn Ki-pt.. p. 11'.'. Lfi 
 1 ( )iii.. Kxp. Sta. I'.ul. in:;, p. p.is. [898, 
 " Kla. Kxp. Sta. Rt-pt . p. 87, L905. 
 
MI GROCER A. 
 
 29 
 
 Orlando. In 1906, E. W. Berger found it on a few whitefly larvae at 
 Leesburg, Florida. 
 
 The effect of this parasite upon Aleyrodes citri seems-tobe of little 
 practical value. It has only rarely been observed attacking this insect, and 
 then does not occur in quantity, as do the other fungi before spoken of. It 
 is not uncommon to find a large amount of this fungus upon Mytilaspis 
 citricola in trees that are at the same time infested with larvae of Aleyrodes 
 citri on which no fungus can be found. 
 
 LIST OF INSECTS PARASITIZED. 
 
 A list of insects reported to be attacked by this fungus is here given, 
 together with the authority for the report and the localities in which they 
 were found parasitized : 
 
 NAME OE INSECT. 
 
 LOCALITY. 
 
 AUTHORITY. 
 
 Alcvrodcs citri R & H ! 
 
 Florida 
 
 H A Gossard 
 
 Aspidiotus cinc\lus Putnam 
 
 Florida 
 
 E W Berger 
 
 Aspidiotus articulatus Morgan 
 
 Jamaica .... 
 
 T D A. Cockerell. 
 
 Aspidiotus articulatus Morgan . 
 
 West Africa 
 
 J Parkin 
 
 Aspidiotus articulatus Morgan 
 
 West Indies 
 
 J Parkin. 
 
 Aspidiotus aurantii Mask 
 
 Australia ... 
 
 D McAlpine 
 
 Aspidiotus aurantii Mask 
 
 Natal 
 
 Fuller 
 
 Aspidiotus aurantii Mask 
 
 Ceylon 
 
 J Parkin 
 
 (Chfysompfutlus) aurantii Mask 
 
 Transvaal 
 
 C W Howard 
 
 Aspidiotus ficus Comst 
 
 Florida 
 
 
 (Cl:i'\soniphalus cioniduin) Linn 
 
 Transvaal 
 
 C W Howard. 
 
 Aspidiotus licdcrac (Vail) 
 
 Florida 
 
 E W Berger 
 
 Aspidiotus obscurus Conist 
 
 Florida 
 
 P H Rolfs. 
 
 Aspidiotus pcrniciosus Conist 
 
 Florida 
 
 P H Rolfs 
 
 Aspidiotus pcrniciosus Comst 
 
 Taoan 
 
 S I Kuwana. 
 
 Chionaspis citri Comst 
 
 Cuba 
 
 Cook and Home. 
 
 Diaspis pcnta^ona Tar" ... 
 
 Tapan 
 
 S I Kuwana. 
 
 l^ionnia fiornnac Tar " 
 
 Mauritius 
 
 J Parkin 
 
 Ischnaspis filifonnis 
 
 West Indies . . 
 
 J Parkin 
 
 Mytilaspis citricola Pack . 
 
 Cevlon 
 
 J Parkin 
 
 M\iilaspis citricola Pack 
 
 Cuba 
 
 F S E'arle 
 
 Mytilaspis citricola Pack 
 
 Porto Rico 
 
 F S E'arle 
 
 Mytilaspis ctti'icola Pack . . 
 
 Florida 
 
 P H Rolfs 
 
 Mytilaspis sloi'crii Pack . . . 
 
 Florida 
 
 
 (L,cpidosophcs} gloi'crii Pack 
 
 Transvaal 
 
 C W Howard 
 
 Parlatoria bereandii Comstock. . 
 
 Florida . 
 
 P. H. Rolfs. 
 
 VI. MICROCERA SP. 
 
 Microccra sp. : Mycelium pure white; hyphae delicate, septate, loosely 
 branching, hyaline, 4 5 microns thick ; conidia at first borne on the ends 
 of the branches, one and two-celled, oval to oblong, 7 12X3 microns; 
 conidial tubercules various in size, cushion-shaped, pink, made up of a 
 compact mass of conidia ; conidia lunate, acute at both ends, 3 to 5 septate, 
 mostly 28 1-0X3.5 5 microns. A few conidia reach 52 microns. On 
 Alcvrodcs citri R. H.. on citrus trees in Florida, U. S. A. 
 
30 
 
 PARASITIC I'l'OX ALEYRODES CITRI. 
 
 DISCOVERY. 
 
 In September, 1907, Prof. P. H. Rolfs, when visiting the orange grove 
 of Mr. F. Wills at Sutherland, Florida, noticed that a great many larvae 
 of Aleyrodcs citri were dead or dying. None of the known parasitic fungi 
 were to be seen, but by the use of the hand lens a whitish fringe could be 
 noticed growing from the edges of the larvae. Specimen leaves were 
 brought back to the laboratory on September 13, and on microscopic ex- 
 amination, the larvae upon these leaves were found to be diseased by a 
 species of Microcera. Leaves sent in by Mr. Wills on September 26, were 
 found to have even more abundant fungus, and nearly all the larvae were 
 dead. Orange leaves sent in from Manatee a few days later were also 
 found to bear larvae infected with the same fungus. This Microcera has 
 since been found at Largo, Bayview, and Safety Harbor by the author, and 
 has been brought in from Orlando, DeLand and Leesburg by E. W. Berger. 
 A preliminary notice of this fungus was published by 
 the author in Press Bulletin 68 of the Florida Experiment 
 Station, "A Xew \Yhitefly Fungus". This fungus presents 
 a fringe of delicate white hyphae growing outward from 
 /j the edges of the larvae (Plate VI, Fig. 41). These hyphae 
 
 at first bear one-, two-, or three-celled conidia, which are 
 oval to fusiform in shape (Fig. 16). Afterwards there are 
 formed on the edge of the larvae 
 pinkish spore-masses, which are 
 
 Kiir. I' 1 ., llyj-liii f 
 Microeera from 
 
 " f cltn " x m ' 
 
 edge of larva 
 showing branch- 
 ing and forma- 
 
 no., of one- and made up of a compact mass of lunate 
 
 two-celled coni- , __. ,_., 
 
 dia. x 1000. spores (Fig. 17). These are 3- to 
 
 5-septate, and -jS to i<> microns long, by :>.."> to 5 
 microns thick, in fresh specimens. When the larvae 
 are placed in distilled water on a microscope slide, 
 the fungus spores are seen to float apart and spread ^om 
 
 out in the water. 
 
 CULTURES. 
 
 Culture- if this Microcera were grown much more easily and quickly 
 than those of any of the previously described fungi. This" fungus grew 
 rapidly on nearly all kinds of media which were tried. 
 
 On September II. I'.in;, the day after the fungus had 
 been examined and recogni/ed as a new parasite on Alc\- 
 rodes citri. three- sets of petri dish cultures of three each, 
 A. U. and C, were prepared according to the usual method 
 For isolation. The first Se1 was made by touching an in- 
 fected larva with a moist platinum needle, and washing 
 the needle off in test-tube A. I', received three loops from 
 A. and T three loops f n .in I'. In three days on petri dish 
 A. two mycelia and a number of bacterial colonies were 
 evident. In nine days, the fungus had overrun almost tin- 
 entire dish, in spite- of the bacteria present, and was pro- 
 ducing an abundance of conidia. \\ and C developed no fungus. 
 
 Fijf. IK. Cr.Ili.1iK 
 
 I-., 111 i, .-i tube '-ul- 
 
 on broiil. X I.Vi. 
 < Cullur.- hud <1ri-l 
 
MICROCERA. 31 
 
 The second set was inoculated with spores from a test-tube in which 
 an infected larva had been shaken up in water. In both A and B, a good 
 growth of fungus appeared. The fungus just showed after ~24~Iiours. In 
 A, in three days, there were about 50 mycelia. In B, in three days, the 
 mycelia, three in number, had become 10 to 12 mm. in diameter, loosely 
 tufted, with numerous conidia on the upwardly projecting, irregularly 
 branching hyphae. In nine days, the growth had covered the entire surface 
 of the medium. 
 
 The third set was inoculated from a test-tube containing a little sterile 
 water, in which two infected larvae had been placed. Only the first petri 
 dish A developed a growth of Microcera, which grew as described for the 
 second set. 
 
 The fungus in all cases was of a pure white color. It grew in loose 
 tufts, with upwardly growing, very delicate hyphae, forming a loose, fluffy 
 mass, which soon collapsed when the cover of the petri dish was removed. 
 A microscopic examination of this growth showed that it was made up of 
 irregularly branching hyphae bearing conidia. 
 
 All intermediate shapes of spores from the oval one-celled conidium, 
 to the septate lunate conidium, could be found in. the same culture. (Figs. 
 1G, 17, 18). It may be remarked in this connection, that in the cultures of 
 Sphaerostilbc coccophila made by P. H. Rolfs in 1897, the conidial stage 
 of which has been referred to Microcera, these one- and two-celled conidia 
 appeared, and are figured by him in Bulletin 41 of the Florida Experiment 
 Station, Plate II. Judging from the growth of Microcera sp. in cultures, 
 it would probably fit into the genus Fusarium, but since the distinction be- 
 tween Microcera and Fusarium is rather vague, we prefer to hold to the 
 name Microcera until the perfect stage is worked out. Perithecia of this 
 fungus appear to be developing at the present time on culture media. 
 
 On September 18, two test-tubes of standard agar, one of Irish potato, 
 and one of rice, were inoculated by drawing a moist needle over the top 
 of culture P> of the second set poured on September 14. On agar tubes 
 there seemed to be some evidence of growth in three or four hours. On 
 September 21 (3 days), tufts of white mycelium were formed over the 
 entire surface. On November 20, the agar had begun to shrink away from 
 the sides of the tube, and the fungus had grown down over the sides of 
 the medium. On Irish potato, September 28, almost the entire surface was 
 covered with a snowy white growth of fungus. On rice in a 50 cc. flask, 
 by November 11 (54 days) the entire surface was covered with growth, 
 and the spaces between the rice grains were packed with a fungus mycelium. 
 The mycelium was very thick, matted, and pink on the sides near the glass 
 (Plate" VI, Figs. 39 and 40). 
 
 On September 25, a test-tube and a flask of rice, and two tubes of bread, 
 were inoculated from the same culture as before. On rice, September 28 
 (3 days), a delicate growth 10 mm. high was formed in the test-tube. The 
 rice had turned pinkish from the top to ^4 inch down on the sides. In the 
 flask almost the entire surface was covered, and was pinkish at the base on 
 the sides of the rice. By October 18 (23 days) the fungus had grown 
 through all the available spaces in the medium, forming a pinkish matted 
 
FUNGI PARASITIC UPON AI.KYRODES CITRI. 
 
 -rnwtli. ( )n November 11, numerous conidia were present in pink masses 
 on tin- sides of the rice. ( )n the bread, on September 28 (5 days), a delicate 
 white growth was formed over the upper surface. On October 10 (15 
 days), the growth had taken up every available space in the pores of the 
 bread. giving it a pinkish matted appearance. 
 
 ( )n ( October 11 the following- cultures were made by transferring spores 
 from the bread cultures of September 25, which had been transferred once 
 before. Three tubes of agar, one of sweet potato, one of Irish potato, one 
 of rice in a .">() cc. flask, and one of bread were used. Notes were taken on 
 ( >ctoher 1!' only. In the three agar tubes, which reacted 1.0, 1.5 and 2.0 
 respectively to phenolphthalein. the growth was about one inch high with 
 abundance of conidia. There was no noticeable difference in the growth. 
 ( )n sweet potatoes, a pure white, delicate growth appeared ; on Irish po- 
 tatoes, a very abundant growth; on rice, an abundant growth with a -pink- 
 ish color on the surface, and thick mycelium between the rice grains. 
 
 INKKCT10N OK AUCYROPKS CITRI. 
 
 On September 1!>, 1!M)7, infection experiments were made on healthy 
 whiten*}- larvae from cultures of this fungus. The larvae were on the leaves 
 of a privet hedge (Ligustnuii ovali folium) in Gainesville. The following 
 is taken from notes made at the time of the experiments : 
 
 Healthy larvae were very abundant on the privet leaves. The weather 
 was damp after a rain. Inoculations were made from 3 to 5 p. M. 
 
 \o. 1. Inoculation was made from culture of September 14; conidia 
 were penciled on the under side of the leaves on one branch with a moist 
 camel s-hair brush ; a piece of cheese cloth was tied around the inoculated 
 branch. On September 21 no conidia were found; the cheese cloth was 
 removed. On September 2<S, no conidia were found. On October 5, abund- 
 ant conidia of Microcera were present. On October 25, about 50 per cent, 
 of the larvae were dead. 
 
 \o. 'I. Inoculation was made from same culture, penciled on as in No. 
 1, but not covered with cheese cloth. On September 28, no spores were, 
 found. On October 1, spores of Microcera were present. On October 5, 
 pink spore-masses were developed on the edges of larvae. P>y October 25, 
 about -V> per rent, of larvae were dead. 
 
 \o. 3. Conidia were penciled on as above, and not covered with cheese 
 
 cloth. On September 21. no spores were found. On September 28, no 
 
 spores were found. On October 1. Microcera spores were present. ' On 
 
 nk spore masses were present on the edges of the larvae. ( )n 
 
 ( )cto],er 2~>. about ."in per cent, of the larvae were dead. 
 
 Xo. I. Inoculation was made from larvae on citrus leaves from Mana- 
 \o cheese cloth was tied around. ( )n September 21. larvae seemed to 
 be attacked by a small fungus, which looked like the Microcera of the 
 cultures. The conidia were one- and two-celled. ( )n September 2, abund- 
 ant spores of .Microcera >n .lead larvae were found, and live larvae with 
 filaments ,,f fnngns within. About (in per cent estimated dead. On Octo- 
 ber "). pink conidial masses were evident on edge's of larvae. 
 
 No. 5, A branch as a check was not inoculated. l,nt tied up with cheese 
 cloth. On September 21, no COnidia of Microcera were to be found. On 
 September 2s. n> conidia of .Microcera to be found. 
 
MICROCERA. 33 
 
 Xo. 6. A branch near Xo. 5 was neither inoculated, nor tied with cheese 
 cloth. On September 21, no spores of Microcera were to be found. On 
 September 28, no spores of Microcera were found. 
 
 X"o. 7. A branch above Xo. 4 was neither inoculated, nor tied with 
 cheese cloth. When examined on September 28, no Microcera could be 
 found. 
 
 During the first two weeks after these infection experiments were made 
 there were frequent rains, and the weather was quite moist. This was fol- 
 lowed by two weeks of drier weather during which the fungus apparently 
 ceased to grow. These inoculation experiments show that under favorable 
 climatic conditions like those under which they were carried on, the larvae 
 of Ale yr odes citri may readily be infected either directly from previously 
 infected larvae, or from pure cultures. 
 
 GERMINATION OF CONIDIA. 
 
 The conidia of Microcera germinated quite readily in water. On Octo- 
 ber 3, a hanging drop culture was made with conidia from a potato culture. 
 In 24 hours, one of the cells of the conidia, usually the end cell, sent out 
 hyphal tubes to a distance of one to four times the length of the conidia. 
 On the end of a number of these were seen small oval sporids (Fig. 19). 
 In 48 hours the hyphae were 6 to 7 times the length of the conidia, some 
 of them branched as in Fig. 19, and many sporids had formed. In six 
 days the branching hyphae were j\ ^r-^Z^ ^!k*" ' ' ' '-^^j-^ 
 
 prominent, with many sporids. The /V^^"*^J> ^^v "*"^^?\ 
 
 segments of the conidia had become if ^\ 
 
 swollen, thus causing constrictions G?3 
 
 Fig. 19. Conidium of Microcera germinating 
 
 at the septa. and forming sporids. (a) Conidium. (?>) hyphal 
 
 tube, (c) sporid, X 450. 
 
 VARIATION IN SIZE OF CONIDIA. 
 
 The measurements of conidia at various times and under various con- 
 ditions indicated a considerable variation in size. The greatest variation 
 was in the length. As has been said, the conidia varied from oval one- 
 celled spores to long lunate spores. Measurements of lunate spores on 
 larvae were as follows : 
 
 On September 23, the first specimen from Sutherland after drying bore 
 conidia measuring 28 40 by 3.5 5 microns. On September 26, the second 
 lot of specimens from Sutherland, while still fresh, contained conidia meas- 
 uring 36 45X3.5 4.5 microns. On October 5, privet leaves from inocu- 
 lation experiment X^o. 4, at Gainesville, while still fresh, bore conidia meas- 
 uring 3152X3.5 4.5. 
 
 Measurements of lunate spores in cultures were as follows: 
 
 On September 17, conidia from cultures made September 14 measured 
 21 32X3.5 4.5 microns. On X T ovember 21, conidia from culture on 
 potato, measured 12 to 30 microns long; two-celled conidia were 12 microns, 
 the others longer. On February 2, 1908, from cultures 101 days old, made 
 October 26, 1907, on white cornmeal cultures not dried out; conidia in pink 
 
34 FUNGI PARASITIC UPON ALEYRODES CITRI. 
 
 cushion-shaped masses, 5-septate, 4060 microns long; most of them 40 
 microns, few 60 microns. On June 2, 1908, from culture on bread made 
 September 25, 1906, dried out; conidia 1530X34.5 microns. 
 
 DISTRIBUTION OF MICROCERA SP. IN FLORIDA. 
 
 Sutherland September 13, 1907. 
 
 Manatee September 18, 1907. 
 
 Gainesville September 21, 1907. (Introduced.) 
 
 Leesburg October 11, 1907. 
 
 Orlando November 25, 1907. 
 
 Largo November 1907. 
 
 Titusville December 3, 1907. 
 
 Safety Harbor March, 1908. 
 
 VII. THE BROWN FUNGUS OF ALEYRODES CITRI. 
 
 In March, 1896, H. J. Webber 56 discovered this fungus on whitefly 
 larvae in the grove of J. H. Viser, Manatee, Florida. During the summer 
 of that year the fungus spread rapidly through the Viser grove, and was 
 observed to be a very effective parasite of Aleyrodes citri. As no fructifica- 
 tion of any kind has been found in connection with this fungus, it has not 
 been classified. It has been known since its discovery as the "Brown 
 Fungus" of the whitefly (Plate VII, Fig. 42). 
 
 INSCRIPTION. 
 
 Webber 57 gave a general description of this fungus in Bulletin 13 of 
 the Division of Vegetable Physiology and Pathology, as follows : 
 
 The mature stroma is compressed hemispherical, frequently having a slight de- 
 pression in the apex over the center of the insect, where the hyphae come together as 
 they spread from the edges of the scale in their development. The size varies greatly, 
 according to the stage of development of the insect attacked. In very young larvae 
 it is from l / 4 to l /2 a millimeter in diameter. In mature larvae and pupae it frequently 
 reaches 2 millimeters in diameter. The thickness, or height, also varies in like manner, 
 specimens on mature larvae or pupae being usually from 175 to 260 microns, while 
 those on young larvae are much thinner. * * * The stroma is commonly seal 
 brown, with a shade of chestnut, but becomes slightly darker with age. * * * The 
 hyphae, which make up the body of the stroma, are light brown, very tortuous, and 
 but slightly branched. Those in the body of the insect are of similar character, but a 
 much darker brown. From the base of the stroma a ground mycelium, or hypothallus, 
 spreads out in all directions on the surface of the leaf, forming a compact membrane 
 near the stroma, but becoming gradually dispersed into separate filaments. * * * 
 The hyphae of the hypothallus are colorless, sparingly branched, mostly continuous, 
 having only an occasional septum, and are from 5 to 7 microns in diameter. In some 
 places in the hypothallus. where the hyphae are apparently somewhat massed and 
 knotted, tlu-y become light brown, similar in color to the isolated hyphae of the 
 stroma. 
 
 Div. of Veg. Phys. & Path., Washington, 1). C.. I',ul \\\ p. "7 is7 
 Ibid. pp. 28-30. 
 
THE BROWN FUNGUS. 35 
 
 BROWN FUNGUS OF PARKIN. 
 
 J. Parkin 58 in writing of the Ceylon forms of fungi parasitic on Aley- 
 rodes, mentions having found on three different kinds of teav^s a brown 
 sterile fungus, which he thinks is similar to the one described by Webber 
 on Aleyrodes citri. He also states that these brown pustules were in many 
 cases closely associated with Aschersonia aleyrodis of Webber, and suggests 
 the possibility of one being a form of the other. In regard to this point he 
 writes : 
 
 Intermingled with the brightly colored Aschersonia stromata on the leaf of 
 Flemingia strobilifera were other brown ones. Many of these latter were evidently 
 old or arrested Aschersonia stromata, as sections of them revealed closed pycnidia. 
 Others again were flatter, more nearly resembling Webber's brown fungus, thus sug- 
 gesting the possibility of all these sterile pustules being really connected with Ascher- 
 sonia. The two fungi often appear in association on the same scale and even on the 
 same leaf. Webber mentions that A. aleyrodis was present on those orange bushes 
 containing also the "brown mealy wing fungus". In the Ceylon specimen on Meme- 
 cylon the two were intimately associated. Atmospheric conditions such as dryness 
 may also influence the development of the Aschersonia as to induce it to assume a 
 sterile resting form. This, when conditions are again favorable, might send out in- 
 fecting hyphae over the leaf surface. Webber's account of how this brown fungus 
 develops and spreads hardly favors such a view. However, its close association with 
 Aschersonia is a point to be kept in mind. By cultures perhaps this sterile form might 
 be induced to form some fructifications, and so a clue to its nature and relationship 
 might be obtained. 
 
 The cultures of Aschersonia aleyrodis and Aschersonia flavo-citrina made 
 by the author on various media and at different times of year with varying 
 amounts of water, never showed any tendency to develop the brown sterile 
 form of the Brown fungus. In Florida there seems to be no evidence to 
 indicate any connection between this sterile Brown fungus and the Ascher- 
 sonias parasitic upon Aleyrodes citri. 
 
 METHODS OF INTRODUCTION. 
 
 Webber, in the bulletin previously referred to, describes in some detail 
 the method of introducing this fungus into trees infested with Aleyrodes 
 citri by pinning in leaves, or by planting young fungus-bearing trees in 
 such a way that their leaves would come in contact with the larvae-bearing 
 leaves to be infected with fungus. E. W. Berger 59 has recently produced 
 some infection by grinding up the brown stromata, stirring with water, and 
 spraying this water upon infested leaves. 
 
 A number of attempts have been made by the writer to grow cultures of 
 this fungus in the laboratory, but so far he has been unsuccessful. In one 
 case where stromata of the brown fungus were placed close to a drop of 
 agar in a hanging drop culture, short tortuous hyphae were seen to grow 
 
 158 Annals Roy. Bot. Card. Peradeniya, Vol. Ill, Part I, p. 52, 1906. 
 C9 Fla. Exp. Sta. Bui. 88, p. 64, 1906. 
 
:;r, i-r.\(,i PARASITIC UPON ALEYRODES CITRI. 
 
 out from the edge. This is the only growth that lias so far been observed 
 under artificial conditions. 
 
 niSTKII'.r H<>.\ OF THE BROWN FUNGUS. 
 
 Florida. Alva. Bartow, Buckingham, Bradentown, Fort Myers, Largo, 
 Leesburg, Manatee, Oneco, Orlando, Palmetto, St. Augustine and St.. 
 Petersburg, on Ale yr odes citri. 
 
 Ceylon, as reported by J. Parkin, on various species of Aleyrodes. 
 
 SUPPLEMENTARY NOTES. 
 
 1. Since the above has been written, what appear to be the spores of 
 the Brown fungus of Aleyrodes citri have been discovered. These spores 
 are germinating in hanging drop cultures of sugar solutions, and are pro- 
 ducing hyphae that seem to be identical with those of the Brown fungus. 
 Further studv is needed to prove the relationship of these spores to the 
 Brown fungus. 
 
 V. A species of Sporotrichuin has been discovered upon the adult and 
 larva of Aleyrodes citri. This fungus seems to be responsible, during damp 
 weather, for the premature death of great numbers of adults. Cultures and 
 inoculation experiments are being carried on, the results of which will be 
 published later. 
 
 3. Since the writing of this thesis it has been shown by Dr. E. W. Berger, 
 Entomologist of the Florida Experiment Station, that the insects hitherto 
 designated as Ale\rodes citri comprise two distinct species of Aleyrodes; 
 one with smooth eggs and clear wings, and the other with rough eggs 
 covered with a delicate net of five- and six-sided meshes, and wings with 
 a smoky-colored area at the end of each fore wing. Specific differences 
 have also been observed in the first and fourth stage larvae. (See Press. 
 Bulletin t)T, Fla. Agri. E\p. Sta., and Proc. Fla.'Sta. Ho'rt. Soc., p. 86, 1908.) 
 Dr. Berger's observations and also those of the writer seem to show that 
 these two species of Aleyrodes are differently attacked by the Aschersonias 
 (A. oleyrodis and ./. flavo-citrina}, and also by the Brown fungus and 
 Microccra sp. Aschersonia flaz'O-citrina attacks readily onlv the smoky- 
 winged Aleyrodes. but will attack the clear-winged species. Aschersonia 
 ulcyrodis and the Brown fungus attack both species of Aleyrodes in an equal 
 degree, but the greater number of the specimens so far observed have been 
 found upon the clear-winded species. The Microceni has been found on 
 both species of Aleyrodes, although it is more effective upon the smoky- 
 winged .species. The infection experiments described in the foregoing pages 
 with cultures of Microccni sp. (page :;>) and / V/7/V/7/////// hetcrochuinm 
 (pag &4) were made up. .11 the clear-winged species. The infection ex- 
 periments also made by E. \Y. Berger at St. Petersburg and ('.ainesville-- 
 i page 1'i) weft aNo upon the clear-winged Aleyrodes. 
 
 October 1, 1908. 
 
SUMMARY. 37 
 
 SUMMARY. 
 
 1. Entomogenous species of fungi representing many different genera 
 have been described in the past hundred or more years. 
 
 2. These have not, until recent times, been studied from an economic 
 standpoint. The greatest success in the use of fungi to combat insect 
 pests seems to have been attained in Florida, where proper conditions of 
 temperature and moisture are present. 
 
 3. Aleyrodes citri R. & H., known since 1885 as a pest to citrus trees in 
 Florida, has spread to many citrus districts since that time, doing much 
 damage chiefly by creating conditions favorable to the growth of Meliola. 
 
 4. A study of the fungi parasitic upon Aleyrodes citri shows that there 
 are at least six species, five of which have been grown upon culture media 
 in the laboratory. 
 
 5. Aschersonia ale\rodis Webber is the most widely distributed fungus 
 parasite of Aleyrodes citri. It is easily isolated and grown in pure cultures 
 in 5 to 10 per cent, glucose agar medium, maturing a stroma in 30 to 40 
 days. 
 
 6. Healthy larvae of Aleyrodes citri may be infected from cultures of 
 this fungus by spraying a mixture of conidia in water on trees infested with 
 Aleyrodes citri. 
 
 7. Aschersonia flai'o-citrina P. Henn., which was recently found in 
 eastern Florida, is also an important parasite of Aleyrodes citri. Its growth 
 on culture media is the same as that of A. aleyrodis. 
 
 8. Conidia of both of the Aschersonias germinated best in a 5 to 10 per 
 cent, solution of glucose in water. Percentages of sugar above or below 
 this retarded germination. Conidia from stromata dried in the laboratory 
 for more than 28 days failed to germinate. 
 
 9. Verticillinni heterocladnni Penz. has been recently shown to occur 
 parasitically upon Aleyrodes citri. It has also been observed on a number 
 of other insects. Cultures and inoculation experiments show that this 
 fungus is distinct from the "Brown fungus", which it somewhat resembles in 
 general appearance, and with which it is frequently found associated. 
 
 10. The growth of this fungus in cultures is much more rapid than that 
 of the two species of Aschersonia described. 
 
 11. Sphaerostilbe coccophila, known since 1848, is world-wide in dis- 
 tribution, and has been reported on no less than fifteen species of scale 
 insects, in addition to being found on Aleyrodes citri. 
 
 12. Sphaerostilbe coccophila has been used in Florida as an effective 
 parasite in controlling the San Jose scale and other scale insects. In more 
 northern States it has not proved to be effective. It is possibly a weak 
 parasite of Aleyrodes citri. 
 
 13. Microcera sp., recently discovered, has been found in a number of 
 places in Florida attacking larvae of Aleyrodes citri. Abundant cultures of 
 
38 Kr.xr.I I'ARASITIC UPON ALEYRODES CITRI. 
 
 this fungus may be grown in a few days, and larvae of Aleyrodcs citri may 
 be infected from these cultures. Conidia of this fungus vary greatly in size 
 under different conditions of growth. 
 
 1 1. The Brown fungus, known in Florida since 1896, has never been 
 observed to produce spores and is therefore unclassified. Its growth and 
 development on Aleyrodcs citri were described by Webber. All attempts to 
 grow this fungus in pure cultures have failed. (See, however, Supplement- 
 ary Note 1.) 
 
 BIBLIOGRAPHY. 
 
 The literature referred to in this bibliography is grouped under seven heads, corre- 
 sponding to the seven divisions under which the subject is discussed. The references 
 in each division are arranged in chronological order. All but three of the papers 
 have been seen by the author. These three are designated by an (*) asterisk. 
 
 GENERAL, LITERATURE. 
 
 ('88) Forbes, S. A. On our present knowledge concerning Insect Diseases. Psyche, 
 Vol. V, pp. 3-12, 1888-90. (Bibliography, pp. 15-22.) 
 
 ('88) Thaxter, Roland. The E'ntomophthoraceae of the United States. Memoirs 
 of the Boston Soc. of Nat. History, Vol. IV, No. 6, 1888. (With bibliography.) 
 
 ('88) Lugger, Otto. Fungi Which Kill Insects. Univ. of Minn. Ann. Kept. Agr., 
 pp. 380-392, 1888. 
 
 ('92) Cooke, M. C. Vegetable Wasps and Plant Worms, London, 1892 
 
 ('93) Riley, C. V. and Howard, L- O. Insect Life, Div. of Ento., Wash., D. C., 
 Vol. V, No. 4, p. 220, 1893. 
 
 ('95) Pettit, R. H. Studies in Artificial Cultures of Entomogenous Fungi. Cor- 
 nell Univ. Agr. Exp. Sta. Bui. 97, 1895 (with bibliography). 
 
 ('95) Forbes, S. A. Experiments With the Muscadine Disease of the Chinch- 
 bug, etc. 111. Agr. Exp. Sta. Bui. 38, is-.i:, 
 
 ('97) Rolfs, P. H. A Disease of the San Jose Scale. Fla. Agr. Exp. Sta Bui 41 
 1897. 
 
 ('98) Forbes, S. A. 111. Agr. Exp. Sta. Bui. 56, pp. 270-280, 1898. 
 
 ('06) Parkin, J. Fungi Parasitic Upon Scale Insects (Coccidae and Aleyrodidae), 
 etc. Ann. Roy. Bot. Gardens Peradcniya, Vol. Ill, Part I. (With bibliography.) 
 
 ASCHERSONIA AI.KVKODIS \YEHBER. 
 
 ('94) Webber, H. J. Preliminary Notice of a Fungus Parasite on Aleyrodes 
 citri. Journ. of Mycol., Vol. VII, No. 4, p. 363, 1894. 
 
 ('96) Webber, H. J. Proc. Fla. State Hort. Soc., p. 73, 1896. 
 
 ('96) Webber, H. J. The Principal Diseases of Citrus Fruits in Florida. Div. 
 of Veg. Phys. and Path., Bui. 8, Washington, D. C., p. 27, 1896. 
 
 ('97) Webber. H. J. Sooty Mold of the Orange. Div. of Veg. Phys and Path 
 Bui. 13, p. 20, Washington, D. C., 1897. 
 
 ('99) Saccardo, P. A. Sylloge Fungorum, XIV. p. 991, 1899. 
 
 ('00) Hume, H. H. Some Citrus Troubles. Fla. Agr. Exp. Sta. Bui. 53, p. 164, 
 
 ('03) Gossard, H. A. Fla. Agr. Exp. Sta. Bui. 67, pp. 622-623, 190.: 
 
 ('04) Hume, H. H. Citrus Fruits and Their Culture, pp. 547-550 Jacksonville 
 
 Florida, 1'.<u. 
 
 ('05) Sellards. E. II. Fla. Agr. Exp. Sta. Rept., pp. 26-27, 1905 
 
 ('06) Earle, F. S. Primer Informe Anual de la Estacion Central Agronomica de 
 
 Cuba, 1904-1905, p. K.'.>. L906, 
 
 ('06) Parkin, J. Fungi Parasitic Upon ScaK- Insects. Annals of Royal Bot Card 
 
 Peradeniya, Vol. Ill, Part I. ,,. :;r,, i<>06. 
 
 ('06) Berger, E. W. Fla. Agr. Exp. Sta. Rept.. p. xix, v.MMi. 
 ('07) Berger, E. W. Fla. Agr. Exp. Sta. Bui. 88, pp. 54-c.:,, 1907 
 ('07) Berger, E. W. Fla. Agr. Exp. Sta. Rept., p. xxxi. 11107 
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 ASCHERSONIA FT.AVO-CITR1NA P. HENN. 
 
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 VERTICILUUM HETEROCLADUM PENZ. 
 
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 SPHAEROSTILBE COCCOPHILA 
 
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 ida, 1904. 
 
40 FUXf.I PARASITIC UPON ALEYRODES CITRI. 
 
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 de Cuba, l'.n>4-l .(:. p . ]<>:>. i<>06. 
 
 ( (>, ) Parkin, J. Ann. Roy. Bot. Card. Peradeniya. Vol. Ill, Part I, p. 48-49, 1906. 
 
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 1>. :>4. 1907. 
 
 :) Griffing. Fla. State Hort. Soc. Rept, pp. 54-55, 1907. 
 
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 Sta. Bui. 9, p. 22, February, 1908. 
 
 ('DM Howard. C. W. " The Scale Insects of Citrus Trees. Dept. of Agr., Trans- 
 vaal. Reprint from Transvaal Agr. Jour. No. 148, p. 6, 1908. 
 
 MIX) Rolfs, P. H. and Fawcett, H. S. Fungus Diseases of Scale Insects and 
 Winterly. Fla. Agr. Exp. Sta. Bui. 94. I'.ios. 
 
 MICROCERA SP. 
 
 ('07) Fawcett, H. S. A New Whiterly Fungus. Fla. Agr. Exp. Sta. Press Bui. 
 No. 68, 1907. 
 
 WKI'.r.Kk's I'.KOWX FUNGUS. 
 
 "i) Webber, H. J. Proc. Fla. State Hort. Soc., p. 74, 1896. 
 
 ( '97 ) Webber, H. J. Proc. Fla. State Hort. Soc., pp. 55-56, 1897. 
 
 ( <( .7) Webber, H. J. Sooty Mold of the Orange. Div. of Veg. Phys. and Path., 
 Washington. I). C., Bui. 13, pp. 27-30, 1897. 
 
 ('00) Pettigrew, A. J. Proc. Fla. State Hort. Soc., p. 63, 1900. 
 
 ('<><' Hume, H. H. Fla. Agr. Exp. Sta. Bui. 53, p. 164, 1900. 
 
 ('03) Gossard, H. A. Fla. Agr. Exp. Sta. Bui. 67. pp. 621-622, 1903. 
 
 ( '()4 ) Hume. H. H. Citrus Fruits and Their Culture, p. 550, Jacksonville, Flor- 
 ida, I'.HM 
 
 ) Sellards. E. H. Fla. Agr. Exp. Sta. Rept., p. 26, 1905. 
 
 ( '(Mi ) Parkin, J. Fungi Parasitic Upon Scale Insects. Annals of Roy. Bot. Card.. 
 Peradeniya. Vol. III. Part I. p. 52, 190(5. 
 
 ('or.) Merger, E. W. Fla. Agr. Exp. Sta. Rept., p. xix. 1906. 
 
 ( 'i7 ) Berger, E. W. Fla. Agr. Exp. Sta. Bui. 88, pp. 64-65, 1907. 
 
 ('07) Berger, E. W. Fla. Agr. Exp. Sta. Rept., p. xxxi, 1907. 
 
 ('08) Rolfs. P. H. and Fawcett, H. S. Fungus Diseases of Scale Insects and 
 
 Whitefly. Fla. A-r. Kxp. Sta. liul. <)4. 1908. 
 
 i-Xl'l. \.\.\TIO.\ oi? PLATES. 
 PLATE I. 
 
 Fig. 20. . Isclicrsnnid tilcyi'<)dis. Culture in petri dish of 5 per cent, glucose agar 
 pourc-d December 7. 1900; showing mature stroma 36 ..days old. The central 
 raised portion was red, and contained the pycnidial cavities with spores. 
 
 Fig. 21. Aschcrsonia aleyrodis. Culture on rice after 5 weeks, grown at room- 
 temperature. 
 
 Fig. 22. Asclicrsotiiu aleyrodis. Culture on sweet potato plug, after 5 weeks- 
 Grown in refrigerator after first few days 
 
 Fig. 23. . Isclicrsonia ali-ynniis. Culture on white corn meal after 5 weeks. Grown, 
 at room temperature. 
 
 PLATE II. 
 
 Fig. 24. . Ischt'i-stnini fltirn-citrina. Citrus leaf showing stromata of the fungus 
 in the position originally assumed by larvae of .-llcynnics citri. The hemi- 
 spherical raided center was yellow with a fringe of outgrowing hyphae. 
 .':> .--.Jsclicrsitnia dlcynxlis. Citrus leaf showing stromata. The raised center 
 was red instead of yellow, as in the previous figure. 
 
 111. 
 
 M..tsc/u'rs<niia t'laro-cifrimi. Culture on petri dish of 5 per cent glucose 
 agar made -fO.5 to plienolphthnlein. after :;:; days. Culture poured September 
 14. ]'.<><;; showing the mature stromata one and a half times natural size. 
 Fig. ZT.Aschtrsonia flavo-citrnta. Culture on petri dish of 5 to 10 per cent 
 glucose agar, after in days showing ho w stromata will spread when given: 
 room to grow. 
 
EXPLANATION OF PLATES. 41 
 
 PLATE IV. 
 
 Figs. 28-30. Aschersonia flavo-citrina. Cultures on sweet potato plugs, inoculated 
 
 November 1, 1906, after 60 days. 
 Fig. 31. Verticillium heterocladum. Citrus leaf showing fungus pustules on 
 
 larvae of Aleyrodes citri. 
 
 PLATE V. 
 
 Fig 32. rcrticillium heterocladum. Culture in test-tube on bread. 
 
 Fig. 33. Verticillium heterocladum. Culture in test-tube on Irish potato plug. 
 
 Fig. 34. Verticillium heterocladum. Culture on glucose agar, showing brown 
 
 pustules. 
 
 Fig. 35. Verticillium heterocladum. Leaf of privet bearing larvae of Aleyrodes 
 citri infected with the fungus by means of a citrus leaf containing pustules. 
 
 PLATE VI. 
 
 Fig. 36. Sphaerostilbe coccophila. Sporodochia of the fungus on bodies of 
 
 Aspidiotus hederae, on Chinaberry twig. 
 Fig. 37. Sphaerostilbe coccophila. Sporodochia of fungus on bodies of Mytilaspis 
 
 citri co la on citrus twig. 
 Fig. 38. Sphaerostilbe coccophila. Perithecia of fungus on Mytilaspis citricola 
 
 on bark of citrus. Twice natural size. 
 Fig. 39 and 40. Microcera sp. Cultures on rice showing loose fluffy growth on 
 
 top of medium. Natural size. 
 Fig. 41. Microcera sp. Citrus leaf with larvae of Aleyrodes citri infected with 
 
 the fungus. The fungus is shown by white fringes on the edges of a number 
 
 of the larvae. 
 
 PLATE VII. 
 
 Fig. 42. The Brown Fungus of Webber. Citrus leaf with brown pustules that 
 
 have formed on larvae of Aleyrodes citri. (Photographed by H. H. Hume.) 
 Fig. 43. Cladosporium sp. A super-parasite found growing over Aschersonia, 
 
 flavo-citrina on leaf of citrus. 
 
Plate I 
 
 Figs. 20-23. Cultures of Aschersonia aleyrodis. 
 
Plate II 
 
 Fig. 24. Aschersonia flavo-citrina on citrus leaf. 
 
 Fig. 25. Aschersonia aleyrodis on citrus* leaf. 
 
Plate III 
 
 Fig. 20. Cultures of Aschersonia flavo-cilrina. 
 
Plate III Continued 
 
 Fig. 27. Cultures of Aschersonia flavo-citrina. 
 
Plate IV 
 
 Figs. 28-30. Cultures of Aschersonia flavo-citrina. 
 
35 
 
 Figs. 32-34. Cultures of Verticillium heterocladum . 
 Fig. 35. Verticillium heterocladum on Aleyrodes citri on privet leaf. 
 
Plate VI 
 
 i-l 
 
 Figs. 36-37. Sporodochia of Sphaerostilbe coccophila. 
 
 Fig. 38. Perithecia of Sphaerostilbe coccophila. 
 
 Figs. 39-40. Cultures of Microcera sp. 
 
 Fig. 41. Microcera sp. on Aleyrodes citri on citrus leaf. 
 

 Plate VII 
 
 Fig. 42. Brown fungus on Aleyrodes citri. 
 
 1-3 
 
 Fig. 43. A super-parasite (Cladosporium sp.) upon Aschersonia flavo-citrina. 
 

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