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POTATOES CAUSED BY BACILLUS SOLANISAFBUS, HARBISON. PAIL A. MUKPIIY, HA.. A.R.t'.Si.I. Assistant in AriiiistiT iif .Njzriciiltiire, Ottawa. Ottawa. Mnrrh T, inifi. .'^iii:— I liavr till' lioimur to "iiliiiiit luTowitli fur yimr :iiP|iMval. (irculur Sd. 11, till larj.'!-, have in recent years lieen u|i|iieeial)ly i-ediieed a* a result of tlii' elo-e sfidy and -ler-istent etfoct of our plant rai'.Mildfrists, niid it is with a view to making Uikihm t(i our farmers tiie means of eon- trcl found to lie iiin>t efHeaeious that this circular has liceii prepared. 1 Would rcc.immend that it he f;iveu a wide distiihution. especially in the Mani- limc I'roviiiees. 1 have the lionoii'- to lie, sir. Your obedient servant. J. II. OHISDALK. Director, Dominion '' ' ■ tal Farms. DniHioN or BoTASV, Ottawa. Fi-bruarj !••, 1«1«I. J. II. Oridpam:, Em)., 6. Aprr.. Dirc'itor, Exin-rinuiitul t'urm«, Uttuwa. Sir:— r have tlic lioumir ti) transmit hinwltli 8 manu«Ti|it entitled "The Blm-li I-fjr Distense of rotiitiK-« nni-iil by Barilhis ■nluiiiiiapniii. II;irri.o|.." prepared at my request by Mr. Paul A. ilurpiiy. B.A.. A.R.C,Sc.I.. asM.tunt in charge of the plant putlii.loKiciil l-iilil Laboratory for I'rinie Kilvviird Isliniii. The study of the losses witli wliioii the potnto ijr.iweri univer-ally have to contend liHs n-vealed that, while low yield- may le due to unfavoiirul.lc .ultural. elimatic, or Miil eon.litions. yet various di.eaw» an- far more largely rispouMlde for tlie»o often eonsiderable lo-w*. It i» quite natural, tl.irefore, that the -"tu.ly of tli.w' di»ea»e* should rei-eive »i*eial attention from the officers of this division, and this activity ha. already resulte.! in the reduction of a l:iry. proportion of loss. Yet it U essenti. for the profitable raiisinn of [Hxatoes that there sliould W |da.c.l at the disiKihaJ of farniers, short, concise and reliable information r.';!ar.linK the co:itrol of those disoase* which are most important from an economic ^tandiioint. Hence, the special Ircatis.. on " Late n!i«lit and Potato Rot " submitted to you rcently is now followed by one on Black Lcjt. This discH»c is readily n-cognizeil and moreover easy of control. The losses due to this disease, now cabnlatcl by Mr. :Murphy to am..mit to the still large sum of $606,255 for the three Maritime Provinces, were, speaking from my per- foiuil exfK'rience. considerably higher ii few years auM,. This »lis«'ns." is being rediu-cHl every year through o\ir instriK-tions and the spiniial efforts of the farmers, and it is lioiied that Mr. Murphy's treatise will assist in further reducing or. preferably, elimi- nating cit altogether from our long list of important plant disease*. I would respectfully re(-..mmend the publication ..f this numnscript as ('ir<'ular No. n. , . I have the honour to be. sir. Your obctlicnt servant. II. T. r.rssow. Dominion Botanist. THE BLACK LEG DISEASE OF POTATOES ouuwd b} BacUliiH totanUaiiruM. PAUL A. MIHI'IIY. II.A.. A.ll.C.Sr.I. Aiwinaiit in charge of IMniit Pothologicnl Field Stntion t'nr I'.K.I. niui'k Iav i* u cJo«trintiiv«> it« iiii|iriironi'e. Thoy iire clmrai'torizpd hy poh' preen or yellowi-h f(iliii»te uinl the loaves have ii tendeney to poll up. They eeiise to Krow mul ireiieriilly iip|H'iir coniewhut HinnliiT thiiii healthy plants. The branehes look ^tiffer and more upriiiht thiiii nuriiinl, and ihc whole phint i« unthrifty and soon die*. (FIk. A.) The HyniptouiH are very well marked and eonstiint, and, onee reeopnizeil, eiinnot earily be mistaken. If an affeetcd |ihiiif lie pnlletl up one fimlH that it leaven the frround easily. A suspii'ious looking plan; may be tested in this way, for if it he trently pulled it yrill come iiway reailily if it iias the Black J.eg. The part of the stulk which was in tlie soil will bo found to be black and rotten, and thin is a certain symptom of the disea^-e. (Fig. B). Tho set will be found to tw rotten also, and if the eonne<'tion can W- traced it will be seen in almost every case that the rot in stalk and set is continuous. .Since the disease comes from the .set it almi;st invariably happens that if one stalk in a hill ..hows the disease the others will sooner or later show it too. This can bo easily veriried by pull- ing thorn up, when it may be seen that no matter how healthy they np|M'ur the rot is workinjf its way through the lowest part* of the stem, soon to make its presence visible in the foliage. In removin<; diaeaged '•«/», 'I>prefore, the wlioir hill »hould he tahu out. If nn.v new tiil>ers are formed, tho infection spreads to them also alonw: " rhizome '■ or stem on which they are borne. One can often see ''ases in which ' has progressed p.trt of tho way along the rhizome towards the new potato. The '.disease nionifc!-ts itself in the tulicr as a rapid soft rot, which ulwny from tho stem end. (Fips. C, D). On the outside, tho rotting tuber is soft and moist looking, and a bhiekish line under the skin shows the boundary of diseased iiml hi'iilthv tissue. Such n tuber when cut open has eliaraeteristieall.v a black cavity in the centre (Figs. E, F) while the remainder of the flesh is soft hut not much di.scohiured. S.inie- timcs the whole of the interior is filled with a white .slime. Onee the diseiise >:ets into >i tuber it rots almost at once, mid utiiler normal circumstain'cs affected tubers n<'ver live over winter, most of them rotting in the ficlil. I he r(.t .irts LIFE HISTORY OF THE (WrSAL ORGANISM. The disease is caused by one of the most minute of organisms, known as bacteria — the name of which is liacillux tiolnniiaprus, Harrison. This organism wiife first described by Professor Harrison of ^lacdonald College. Various other almost ideutical I'iirnxitit h»rt l)pi'n ilpw-ribnl in otlit-r •oiintriiii uiiiU>r cliffcn>iil iianHo. Tli« oritniii«ni i» farmi'il liy tht» mt-tl i'X(lii»inl.\, iiml it iIih-k rml lin- i.vir in tin- n>i\ ii» fur rnt i« kii iwii. Wlifii u M't wliirli li' tfiniMTiitiirt' of tlii' «iil, wt* up n Nift mt in it. Thi« i» Iroiixmittni • . <• or lo»« i|ii -kly to tint •i>rmo to tli«. Kurfaie of the Brouml, viUtiliiJ off tlwir xiipply of 1ihh\ MoTv tltt'ff hn* Ufii tinio to (li'vi'lop much of » root i>y»tfm, iii> plnnt n'«tilt». It iiiori- often hapiuMw. how cviir. thiit tho : hint in nix niii-lH-rt or a f«>uHi hy thu rolliiiK Of it* U'ovi'n anil by it» liifht jrrifii i-oh.iir. Tluw ore inviiriiihli- xiiinii of the wutor »upi>ly U-inu uliort. ami thiit i\» tho proximate i-biim' of thi- nymptoiii* in thin pane aliio. In 'oiiMipu'iirK of tho dini'um' haviiiir tiiki-i hinjji'r to travt-l from tli« M't into tho bane of the »li(Mit. tho plant hu» huil time to >'.'Vfh>|i a lar(«> root •y«t«'m Thiii, unlike •111- rnw ••f tin- •hoot whiih wa» killoil ii« wMin « iit» ronnwtiim with tho Mt wan rut off, the plant is able to live ami thrive hy druwiii,- i>n it* own not* whieh are develoiieil above that part of the »tiilk in whith the paratit 1 1. Oradually, however, tho rot worki upwardu, killiiiK off root after rtK)t, and ilowly ttarviiiK the plant. The rot travels up ai fur as the ground level, and sumetiniit a little .^bove it, and thun cut* o(T the la»t root and finally kilU the plant. If death liaN not reitulted Uforo nome tiiborH have litn-n formed tlu' diwane \* likely to invade them «Iim> ulon : thu rhizome*. If it dwn, they Renernlly rot inlirely iiway. Suoh tubera are not iit all liki v to bo used for imhiI, but there arc other appiin-sitly licalthy one« whieh eontraet tht infretioii from them, or in eomo other way not well under»toon eliminateil that, for wmie ren^on, the paraute may cento to develop in a tiilK-r'and may lie there in a dormMiit romlition nnlil the followintr cprinir. althfinjth it .',. or f'i.(ir> pi-r acre with aiv average yield of ISi bushels. • At the Kxpcrlnient Station. Orono. .Main <•. tO.NTIUH.. DIai'k l.4nr of the m<>«t riKily cniitrolliil of ull |>liiiil iliKcanci*, am), if the iliri'i'tiiiiiii If til tile ('lifup uiiil niiiiplo trriitiiii'iit iiiviii U'luw In- I'iiIIukiiI, it I'liti li' t'litiK-ly i-rnilii'iitril Iti t«M> .vriirK. (Inn' it lui- l»iii I'lliiKlinl it I" imt likely tliiil it .\iJ U> ilitriHlltriMJ nuiiili lililr-t Ire li miiI Ih> |ir(H'iir<'il. Ni'W •iiil •limilil III' iil\\ii>'> trrtlti'il by one i>f lln> iiirtliiMli uiin'ii in nrtii-li' (:l), |i-i!'i'riilil.v with riirrii-in' "iililliimtf. A" oiiuc't' of |irrviiilioii i« licltrr thiiii n inhiimI uf riiri': othiT«i'>i' o:ii' iii'viT kiiii\v« wliiil srriouit (lijH'iiw limy li(i'oiii<> i'»||ilili«hci| oii the fiiriil. Altlioiiuli lliii rfcotiiltiriuliiti'in ii ilo'ilily ii|i|ilii'iili|i> to iii'W wi'il, IK) U'ttiT pruc'tii'i' filll lit' follownl tliilll to illiilifrit ii'Uiiliirly nil M'i'd |iotatiH>ii. liiuKcr, fU'iiiu'r uiMt.ht'iiltliicr c-ro|ii< will In' tlif iiivurinlilr rc'tiitiii". iiml I'Ut tu utliiT i'ru|i> a* lutitf u* tiomiblf. MI'LRN r>m TIIK rilKVTMUNT l>V HKKII II i r \Tl IKX. (I) Do not, if |Niiiaibli>, iikc mkhI from ,n fipUl in whi<'h there vvi» a lure*' niiioiint of Black I^ir, or in which nii«' likilv tn Ih- enrriiil. Xo «li«infc<'tion will be entirely Kiirreiiiifiil tinloH thi* i* done. (3) Steep the nelei't4'il nound (NititiH-^, before eiittiiig, in either: - (a) iMiliition of two oiincci of eorroaivc Kiiblimnte in iT. (."iHoik of wiiter for three hour*. f'oiTnuirc Bullimale i» a ilcnilhi liolnnn. or ('') n MiliitiiHi of .ine pint of formalin in "" ;:iilliiii- uf watrr for two lionK. (4) Keep II jar of forinr'iPa with a sp-.irc knife in it iit hand wlien cuttiiiff need and if a tuber whirh t.ows traees of rot lie met with drop the knife with whii'h it ha* lu'eii cut info the disinfeetniit mid ui-e the other one iiutciul. (.">) Do not plant |Nitatoes in Miil whu'li iieetU draining. A wet -oil favour* the disease. XOTKS ON TIIK I'UKI'AHATIOX AND I'SK OF TIIK 1HSIXFE( TAXTS. Corrii-ive MildiMiiti' i* ftln'r in-cdiilile anil n finull (piaiitity of Imt water ^lllllllll be Used to I'iii^olvo it. Wooiliti or I'lirtliniware vessels only clioiild 1m- ii'-ed t n'aiii it. an it li I" a eorrosive iicliiiii on metal ones. The -olutiun lot-es its >treiijrtli i|iiiekly wlnii a bateli of (xitatoes has been ^tet-|M•d in it, ko tliat it is safer i ot to use it fur .i mc n I lot. The Holntioii will, however, keep (rood for a enii«deralile time before 1 eiiiR u>ed. .Vs eorrosivt siiblimnto, even i-i very dilute feidiitionn, is a deadly poison, the (jreutest eare must be taken with it and with the vessel and potatoes with wliieli it eoiiies in eoi-taet. On im aeeoiint shmilil the iMifafoes be u.-ed for f I for man or lieast, and the eontinim-rs sboiild lie earefiiily wasi.eil befnre beiiitf used for any other piiri>ose It i>, however, one of the licst disinfe faiits known and eertaiiily the most efTeetive known for lotatoes. Its eliea|iiiesd is another point in its favour, an ounee eostiiij; abort 20 cents. On the other hand, formalin possesses leiie of these disnilvantapcs, but it is infor- lunately not so etfeetive for nil potato diseases as tlio other. It as equally g 1 for Black I.etr. Conimon senb and pos-ilily some others, but not so jfood for Khizoetoni:! nor jirobabl.v for Powilery Senb. It is very easily prepared and is non-poisonous, and treated jiotntoes may be used for fond. It may lie used more than imi-o on the same d a» it is made up. but not afterwunis because the formalin evnporntcs. It ean Ik- sold at a profit for 2."i cents a pint but .'iO cents is usually demanded for it. Fur further informafiion apply to the Uominion lintnuist. Central Experimental Farm, Ottawa. Read also — Potato Diseancs trnnsmitted liy the iiw of tingoiind Seed. The poiitrol of Potato Disoases. Potato Scab. Po\vd»>r>' Scab of Potatoes. Free on re