UNIVERSITY OF CALIFORNIA. 
 
 AGRICULTURAL EXPERIMENT STATION. 
 
 BULLETIN NO. 50- 
 
 Whale-Oil Soap Insecticide Washes. 
 
 Among the ingredients of insecticide washes 
 intended for summer use, or on evergreen trees, 
 whale oil soap is one of those most commonly 
 eniplo>ed, as well as moat generally approved, 
 in California. Ic its quite effective in numerous 
 cases, even when used by itself; but it is most 
 commonly combined with, ormade the vehicle for, 
 other insecticide substances. Instead, common 
 soft soap is also employed, but its chief merit lies 
 in the fact that it, in common with other soapy 
 compounds, serves to conserve the efficacy and 
 maintain the action of other insecticides for 
 which it serves as a vehicle. This it does 
 partly by virtuje of its property of promptly 
 wetting even hairy, greasy or polished surfaces 
 (whether of leaves or insects), from which sim- 
 ple water would rebound or gather in ineffect- 
 ive droplets; partly because it remains more or 
 less moist, and in that condition forms a soft, 
 clinging varnish under which the action even of 
 volatile agents (such as kerosene or the extract 
 or powder of "buhach ") can continue for some 
 time without too much wasting of their strength 
 into the surrounding air, by evaporation. 
 
 But whale-oil soap possesses the additional 
 advantage of having, within itself, special 
 odorous substances of insecticide qualities, 
 which impart to crude whale-oil its intensely 
 disagreeable odor. From these it is partly 
 freed, in the refining process, by the action of 
 a certain proportion of caustic alkali (mostly 
 soda), which takes possession preferably of the 
 odorous compounds of the crude oil, together 
 with a certain proportion of the inodorous fat 
 oil. This soapy mixture constitutes the 
 " foots " of the refineries, and is far more en- 
 ergetic in its insecticide effect than soap made 
 from the whole of the crude oil, which contains 
 a relatively much smaller proportion of the evil, 
 smelling substances. 
 
 This fact alone explains much of the diver- 
 sity of opinion that has arisen in the matter of 
 proportioning the strength of the soap washes 
 to the desired effect. For not only has the 
 acap made from the whole oil been supplied 
 by some manufacturers, but those using the 
 washes have, in many instances, made the 
 
 soap themselves, in accordance with the com- 
 mon process of making soft soap at home. 
 
 Matthew Cooke, in his excellent book on the 
 repression of injurious insects, prescribes that 
 one pound of the soap dissolved in one gallon of 
 water shall constitute the basis of the washes. 
 Some have found this wash unnecessarily strong, 
 while others have found it too weak to accom- 
 plish anything. 
 
 In a bulletin issued in February last (Nc. 52) 
 were given the analyses of sundry brands of 
 " lye," from which it appeared that they differ 
 in strength as much as 500 per cent; so that a 
 person using the proportions prescribed for one 
 kind, would, in using the other, make his wash 
 too strong or too weak, as the case might be, 
 to that precise extent; either w asting his work 
 or perhaps scorching his trees. 
 
 An examination of the several brands of j 
 whale-oil soaps in the San Francisco market has ] < 
 revealed similar differences between them. In 
 this case the inert substance present to excess 
 in some samples is simply water, which was 
 found to range, in different preparations sold at ', 
 the same price, from 21 to as much as 82 £ per 
 cent. Curiously enough, the most highly 
 watered article was among the most salable; 
 the reason being, probably, that while tiie 
 article having nearly 80 per cent of soap and 20 
 of water ia somewhat difficult to dissolve and has 
 to be boiled, the one in which these proportions 
 are reversed can be made into a wash by simply 
 stirring it into cold water. But apart from this 
 inconvenience, the one is actually and indispu- 
 tably worth fully four times as much as the 
 other, for the purpose it is intended to subserve; 
 provided that the user will take the trouble to 
 put. in the water himself, instead of having it 
 shipped to him from San Francisco. 
 
 It is no wonder that the experience of fruit- 
 growers differs widely as to the efficacy of whale- 
 oil soap in ridding their trees of insect pests ! 
 
 From a comparative examination of the 
 samples on hand, it appears that a whale-oil 
 soap containing about 50 per cent of water is as 
 readily dissolved as any moderately energetic 
 fruit-grower need desire; and, in view of the 
 relatively small weights of invoices usually 
 shipped of this article, I suggest that it would 
 be convenient to user3, if all manufacturers 
 would adopt the standard of 50 per cent of dry 
 soap to be contained in whale-oil soap, as 
 offered for sale. There will then be some defi 
 nite meaning to the prescription of " a pound to 
 the gallon," and disapointments after the proper 
 use of washes prepared according to the best 
 experience will cease to occur. 
 
The Sulphuring of Vines. 
 
 A number of letters making inquiries regard 
 ing the proper time and mode of using sulphur 
 for the prevention or repression of mildew on 
 vine?, suggest the propriety of a summary 
 statement of the subject, for the general benefit 
 of those interested. 
 
 The first question asked is whether sulphur- 
 ing should or may be done while the vine is in 
 bloom. There is much contradictory evidence 
 on this subject. From an outside point of view 
 it seems undesirable to place an antiseptic, in- 
 tended for the destruction of minute vegetable 
 life, in immediate contact with the extremely 
 delicate tissues of a flower in process of fructifi- 
 cation. The action of the pollen on the p'siil 
 itself involves a process < f genuine growth, 
 which cannot be supposed t) bs favorably in- 
 fluenced by the presence of an agent hostile to 
 other vegetable life. Still, as in the case of the 
 buhach or insect powder, which, however fatal 
 to fleas, is innocuous to man, it is possible that 
 what is very deadly to a minute organism like 
 mildew may pass hirmlessly by even the deli- 
 cate stigma and pollen tubes of the larger vine. 
 No special warning, in the premises is given in 
 the latest European and American works on 
 viticulture, and it must be presumed that no 
 obvious or constant bad effects have been noted 
 from sulphuring blooming vines. It is true, 
 however, that elsewhere the time /or sulphur- 
 ing is usually very much later than is found 
 necessary in some parts of California, where 
 mildew often starts in May; hence, perhaps 
 Californian experience on the subject is more 
 extensive, and it is somewhat conflicting. 
 
 Decided injury has been repDrted in some 
 cases; in others it has been noted that vines 
 sulphured during bloom have "set" fruit 
 abundantly, while others close at h md and not 
 sulphured have been subject to coulure to a 
 damaging extent. In such cases it must be j 
 inferred that the coulure was due to a fungous ; 
 parasite which was at work on the bloom, and 
 which was suppressed where sulphuring was 
 done, but was permitted to do its work where 
 the antidote was omitted. 
 
 As regards the reported cases of obvious 
 damage from sulphuring into the bloom, some j 
 clue to its possible causes was afforded by the ' 
 examination of a collection of samples of com- \ 
 tnercial sulphur exhibited at a late meeting of i 
 the Santa Clara Viticultural Society. Among 1 
 eight samples of California ground sulphur; 
 there were three that possessed a strongly acid 
 taste on the tongue, evidently from the pres- j 
 ence of sulphuric acid. It is quite certain thatj 
 if any sulphur so contaminated were introduced j 
 into an open grape flower it would effectually 
 destroy the vitality of any pollen or pistil 
 touched by it. No such acidity was perceptible 
 in any of the samples of French (sublimated) 
 sulphur exhibited at the same time, although 
 one would more reasonably expect to find it 
 there than in ground sulphur, in view of the 
 usual modes of production. 
 
 Considering the whole of the facts before us, 
 I would advise that sulphuring should be done 
 
 before or after bloom rather than during the 
 same; and that all sulphur used at such time, 
 especially, be carefully tested on the tongue to 
 ascertain whether or not it contains a percepti- 
 ble amount of acid. All such should be dis- 
 carded from any use whatsoever in the vine- 
 yard. 
 
 Regarding the mode of application, I have 
 previously given my reasons for preferring to 
 have sulphuring done while the leaves are moist 
 with dew. The powder then remains adherent 
 to the leaves instead of being blown away by 
 the first wind; and thus the disinfecting action 
 is maintained for a length of time as it is neces- 
 sary it should be, since the effect is not instan- 
 taneous, but depends upon the gradual forma- 
 tion of sulphur vapor. The latter is formed 
 more or less at ail ordinary temperatures, as is 
 obvious from the well-known odor which is 
 especially striking when a sulphured vineyard 
 is under hot sunshine. There is not, as has 
 been erroneously stated, any combustion under 
 these conditions, and therefore no generation of 
 the "sulphurous gas " which serves as a disin- 
 fectant in wine cellars. Moreover, any parti- 
 cles of sulphur lodging on the soil and becoming 
 mixed with it become useless so far as the for- 
 mation of sulphur vapor is concerned, becaase 
 that vapor is promptly absorbed by the soil. 
 Only relatively large masses of sulphur falling 
 on the ground can exert any effect on the 
 vine; but whatever lodges on the head or in 
 the crotches of the stock will, to the extent of 
 its surface exposure, contribute to the forma- 
 tion of the disinfecting vapor. The most eco- 
 nomical and effective use is, after all, the even 
 dusting-over of the moist leaves, on whicn the 
 particles will remain fixed until evaporated. 
 For young vines the dredge is most convenient; 
 on older ones the bellows having a positive 
 provision for agitating the sulphur powder 
 wi hin is preferable; without such provision 
 the distribution is very uneven and wasteful. 
 
 As regards, finally, the choice between ground 
 and sublimated (French) sulphur, the two are 
 doubtless of equal efficacy wheu made equally 
 fine, and, whi)«; differing considerably in price 
 for equal wtigh's y there \s really little difference 
 in the cost of equal bulks, which is the praeti- 
 cal basts of comparison. Both the touch and 
 the microscope show that the ground sulphur 
 is prevalently much coarser than the sublimated, 
 and the large, smooth, shining fragments of 
 the former roll off and are blown away from the 
 leaves much more eabily than the minute, rough, 
 roundish grains of th-* sublimated. Of course, 
 the tatter could be prepared in California just 
 as well as in France; and, judging from the 
 samples lately examined, it would when so 
 made bj more certain of not containing injuri- 
 ous ingredients than is some of the sulphur 
 now offered, which has probably been made 
 from crude, natural volcanic material, instead 
 of such as has been purified by previous melt- 
 ing from the acid with which it is almost 
 always contaminated. Arsenic is another com- 
 mon impurity of native sulphurs, and would be 
 very objectionable in an application to a bloom- 
 ing vine. E. W. HlLGASD. 
 Berkeley, May 17, 1886.