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Lorsque le document est trop grand pour etre reproduit en un seul cliche, il est filme a partir de Tangle supeneur gauche, de gauche h droite, et de haut en bas, en prenant le nombre d 'images necessaire. Les diagrammes suivants illustrent la methode. MIC»OCOfV lESOlU^ION IBT CHAIT ANSI ci.id ISO TEST CHART No 2 I I.I 1.25 ;:i« Ilia t If m 1.8 u ^ -APPLIED IM/1GE ^ i SSXi n^ FRQjN imv |voi.9Ki vr.' :QmTMtMfrojt:^Q:Js T ObsenratioflfjiMi IIm^ f»l»^r Isaria f\ Dr. Wrii. .■<:iiiiiiIit~. r'.lt.SC, :iiii| rv.ni .'Tili S,|.iiiiil,. r. I'llii . The fun IS on \vlii<-li I wish to roconl :i few o[)scrv!itions i-. as no (loulit you ;i I- jiwarc. one of tlic coniinDnrst of those fouii.l ;rro\vini: on insects, at some time or other (hirin;; (HiTereiit stajtes of their (le\elo|)- nient. Far^'reater importance has lieeri attacheij to these entomoi;enoiis fiiiiui in recent yi-ars owin^' to their heinn feL'anled as natural factors in the control of insect pests. 'I'liis i|uesti(iii has intere-teil both IliUo- iiiojoiiist ami Botanist alike and, owin^r to llie ahirininji increase at the proeiit (lay of the larcli sawlly on l>otii sides of the .Vtlantic, n special study of tliis particular fun;;us has been made more opportune. Theif were .several points of interest on which further research was desired. Was the fun>;us known to o( i ..ii the larch sawlly cocoons in llunipe identical with that observed in Canada' This is, however, one of the minor |)oints at issue. Still more |>romiiienl was tin- ipiestion -llops this luiu;us attack the liviin; cocooiis, or the ])upatini; larva' or is it only seciuidary, u'lowin;; saprophytically on the dead cocoons'.' The third point of interest was to ascertiiin how infection took place. I. The first point whs easily settleil. Material i.e. larch sawfly cocoons collected by Dr. C. (.iordon Hewitt in Canada, showed small patches of a whitish fungus K^owin^r on the surface. The cocoons weie kept under suitable condition.s for further study of the futisus. Some three weeks later the jirowth had become elon;;ated and had taken the shape of the cl-.aracteristic forked or toiifiued sporophores with whi<-h the investigator is (piite fiimiliar. These measured from .':> centimeters in length; their stalks were orangc' coloured at the ba,-tr...MM. TIkw vv.t.. t.;.n».frnr.l I.. a .t.'iilr \»-u\ .li.-l. r(.i.t!iiniMii Stan.hml Nuliifnt (i.'laimf. \Uvr M, hour- Miiull la.liHlii.n .-..l.mi.'s U'Ciiin.- visihlo to lli.- uiuikUmI .•>■<• I'lvviou-lv ilir t:.Tmiiiii,i f tl.r r..l..iirloii,. oviil-slmix-.l ("nitliu w,- ol.-crv.l will, til.- ai.l of tl,.- umros,ui»-. Aflrr 0 lu.urs th.- first .iirn, nf n,TM,ii,aii.m .MTmir,!. ihr .[".iv MMi.linL' fnrtl. >nu- or two til,.- iiivc.'li:il l'il..->. S..iti.'lirii.'s til.- ;;.-nniii!.noii aii.l .l.-v.-l..|>m.-ni ,.,,,nit,a..l .m a.T.,..i.t ui th.- tniirl. .-.ilarp-.l s|.lu-ri.ul .rlU pro.lu.-o.l, .,f tl,.- .l.-v..loi.ii..'tit of .•oiMiMon v.-aM siM.r...; at oth.-r tin..-s th.- u.-rtnmu- tioi> r.-s..!„l.l.-a more at. oniii.ary l,yi,hoi..y.'.-tou..* fm.tins. Tlu- yrowtiiK ,..,l„„i,-s fonu.'.l l».autiful ol.j.-rts. Kailialii.^' froi.i tl..- c.-i.tral sp..r.- th,. iivi.li:.' pro.lur..,! cir.'ular ray^ whi.^h uppcar.-d ^ll;:htly iri.liMont wli.-i.'l.oMiiii: up tlu- .li.-l. aii.l lookit.n at tl..- ...lotiy tl.rou«h th.- nu-.liiit... \ft.T a f.'W .lav> 111.- .-..irfac- of llu- p(-tri .lisli aii.l of 'slants" iii t.-st- tiiU- l..-.ai...- iov.-r.-.l with a ,l.-..s.- it.ass of tufty hyi)ha- ot a .•r.-ai.iish .,, ,,al.- oraii^o tii.K'.-. Small porti..i.s ..f th.-s.- w.-r.- .•ar.-fi.lly ri-i....v.-.l aiul .•Nai..ii..-.i. Al.uiiciant sp„r.-s ha.l l«-.-t. pr.ul.i.'t-.l in th.- i.u-ai.tim.v They an- l.on, in Ion- .hains fmn, •-•-11 "ti fin.-ly .Iniwn out (!ask"hap.-a .i.-riginata whi.h at.- i-roaun-.l f...iu th.- main ..r lat.-ral hran.-h.-s oi ,iu- mvc-iium in ■■\vho,l>' fnm. 2 to 7. Th.-y w.-r.-. l.ow.-v.-r. al.n .,l,s..rv't-.l sinjilv. Th.- sp-.n-s pro.lu.'.-.i in tlu- .-uitun-s s..w.m1 th.-n.selvos all around th.- jin.wini: fun-^u- n.a.s.-.< and n.-w ,■,,1...,..-,- w.-r.- ....nstantly „l,..-rv.-d and watch.-d. Tlu- spor.-s an.l st.-rif:n,ata w.-r.- m.-asur.-d ■ind w.-r.- foun-l idrntical it. .-v.-ry r.-.-p.-.t with thos.- },'rown m pun- ..ultun- in.tn i;urop.-an mat.-rial. The fun«us ..n tlu- Cal.admii .■u<•.)on^ lu-nn- was idt-litifi.-d as Ismin furiiuisit. II. Tlu-r.- has l..n>: In-.-n th.- .■on.-.-plion that ls,m,i f,ir„i.,^,i ^-row- parasiti.allv .m ins,-ct larva- of various kinds. All t.-xtl.ooks of my- ,.„l„.-v a-r.-.- on that p..int. In th.- ahs.-n.-.-, how.-v.-r (at l.-ast I was not abh- "to disrov.-r anv ivcords), ..f .U-nu.nstratin- .-xp.-rimi-nts, tlu-s.- stat.-m.-nts did not .-x.lud.- the p..ssil.ility thai tlu- Isnna may o.-.ui s,M-.,ndarilv. It was ju>t as lik.-ly that it nn-w .saprophyti.-ally o„ .-...•.Hms or larva, that had di.-.l pr.-viously. In v»-w ..f tlu> fart thai th.- lan-h sawllv was inrr.-asinfi h.-r.- an.l .-Is.-wlu-r.-. it was tl.ou-ih. advisal.l.- that tlu- [.arasilisn, of tlu- fundus, if su.-h .-xist.-.l, woul.l plav an imp..rtant roh- in the contn.l of this .-n.-my of tamaracks. I niu-t thank hi-re mv fri.-nd an.l .-..ll.-agu.-, Dr. H.^witt, for plariuL- „mt.-rial in form ..f /.s-.(r,.i ...v.-r.-.l lar.h sawfly rot-oons at. my .lisp..sal Tlu-s.- .ocooiis w.-r.- i.hiCL-d l..f:.-tlu-r with the moss in which they w.-rc i„,port.-d from I'nfrlan.l into a Hat «lass ,lish. The moss was nu.ist.-.u... and a well-fitting li.l pr.-s.-rved the in.)islur.- satisfactorily. 'Ihi- iilfl!ililr ijiiiilililv iil' -|KHii|)li(Hrs iil tin- hiirui wtTf proiliii-cil, ( >riniiiiilly 2;{ i n* A\i\\\\\\)i tlit> wliitf imtclif.-* of tin- fiiiiKii- wcH' |iliic»'tl in tlin cHKi'. No iiiliilt inwrt «'iM<'ri:t'il fnun tlifsc (■()ciMiii>. SoiiH* of till- ciHiMiiK* were liiKwctfMl iil iiiti>rval.'4 and wtTt- fiiiitjil l<> contain a lilarki-nnl or ilirty yi'llowi^h aclult. 'I'lif iii«>frti'ii ciMcioh.-' wcrt' rc|>lar«'(l anti the Isiinn (1cvcIo|m'iI liirtlicr. I llicri nh- lainril a lianilful of cot' ioti.« wliicli witc calofully cxaliiiiifil and wlirili >h(iwiMl no .>ii;n!' of an infection wliati'vcr. They were divided in e(|ual iiiiialM'rs, H(l cocoon- >ervin^ in each of the foMowinc experiment.*: ■Im'kkimi.n r A. These soiind livinir cocoons were introduced into u lireeiliiiK chanilier and were carefully kept free from external inl'ection from Isnrin spores. It was sought to a.-icrtain how man\ of the cocoon- wonlil produce liviiii: adults and those eiiier^'ins were carefully n-corded. Ten adult larch sawflies etnerjred in the cour.se of ten days. Kleveii parasitic in.sects were also found to emt^rjie from the cocoons; the remaindi'r of the ciK'ooiis did not "hatcli" at all. Some of thcM- were found, on dis.H'ction. empty. Some showed remaitis of a dead adult. Only one co(ciiin .-howed sif;ii:< of Imirin. I'.Xl'KHIMKNI- H. The siame niimU'r of cocootis were useci. These were placeil tof;(>ther with infested moss and Isnrin spores hearinj: cocoons, into a small breeder. After 10 days (i adults and ti pura.sites were ohservnl and were left confined in the caj;e. One of the first peculiar sym(>t(un> ol>s<>rved in these cocoons was u darkeniiiK in colour of l(i of them. The colour of the normal cocoons lieinj; li,i;ht chocolate, while in the>e cases the colour was of a pronounced dull chocolate linye. Four more adults emerged on stihsequent occa.sion.s. .\lthou;:li no sif;n> of ludrin wei-e then noticeable on the darkening cocoon.s some of the>n were dis.^ccted !ini| inicro.scopically < ■'"mined. Two of the e\aminehowed fuii^'al liyplue in the dead adults' body. Later on white llulTy |)atihes occurred extprnally rather suddeidy on most of the remaining cocoons. I'roin the appearance of tlie.-e funirous >;rowths it was evident that thev were formed liy the Isnrln. About two months after lieirinniiiK the experiments the fungi formed the well-known ftirked sporophores and the inicrosccpical characters proved the fungus to be Isan'n. Spores had be«'n produced abundantly at very early stages and no doubt had become disseminated throughout the cage. When about thive uumtlis I I I i m \ i'i , i y. It. lYAI. SIM II TY Ol CWADA altiT ^.tiirlitii.' ll'i' rxix i^ini-i.l I i>\iiiiiim'.l Ihf inli-rior of llii- ingf BRHin, I tniin.l til.- \\\u<\<- 111.'" Mi|..Tli(iiill\ iiiid iliiniii:h..iit till' liiytT -imlilcl with tiiH- wliiii-li . .il'.iiit- ,,t iiinv'i. 'riif-i- wi'iv i-Miiiiinftl iiiid t' ii"in!iiii.-(l up to .liitr mtv iiiiiuiK-, lull ni'MT «li!«ii|>|'«'!»r«'^'»i''lv "PI"':'"''' •"•'' "<■ pr<-.';ii 111.' iii.'-'^ i" iHMMiliaiiy r.ni.l.l«'.i all ■•vit with iniiiiitr /-in-i ,.„l,,„i..- II .loin.- hiiviiii: no hii|.|.Iv of .•.■nuciiiai I I n'tnaitii'.! Miiall aii.l w.'iv of fours.' of .starv.MJ ap|H'araii.'<'. I ii.'\t .-.•parali-a a f.-vv an.! traiislVrrcl tl't-tii to a ix-lii .li-li .•oiitaiiiiiiL' iiutriciii p-latini'. Il.-ri- tJK'V iiia.li' thn-f (lays' rapid i;r..wili nii'l H" 'l.'nl" w.iuM havi' rovi-i^-.l in till' ii-umI way till' wh. ill- siirfai'.'l.ul l..r th.' app.'arMi,.i'of u'l'latiii.' Ii.juify inn l.a.tclia ^vliicli put a piviiianir.'.'ii.l t.i my ..l.wivali.iii. Ni'viTthclc!*". it was prov.'.l i; ••.•atclly iliat tin- fuii^'ous npots c.msist.'.l of Isarut f,irni„s„ ali.l 11.. olIi.T. It wa> Miipiisilin t.. IIK- that, n.'V.T tlir..U«ll«>lll thi'sc .Api'iiiii.'nts I wa- al.l.i U< oI.s.tv.' ..iIi.t fuimi; likt- I'nunUiiiw aiHJ .ilhi'i- .■..Million iiioiil.U. Scv.-ial inipoilant .■onclusioiis may I"- .Iriwn fi.mi ili.-.' cxpcriiiiciil- I. Hiaiiicl lliai 111.' .'.'.■...Ill* usc.l in i'\p«'rinn'nt> A .ui'l H wiTc ii. cipial .■oii'liiion a- far a« llii'ir Iw'iii^' ali\i' i- c.in.'crn.'il. it i- -li.'wn from till- uri-atiT niimlx'i of a.liills or parasites .•m.'i-uiiiL' fn>m caL'f (.'Xpcn- mi'iit .\> all'! fr.im iIk- infi'.ti.in of a lar^c pr..p.irti f coi'o.ilis in cx- pniiiii'iit H ihal ll' fuii'^iis Is.irio fnriniMi is liuly pai'a-iii.' on lanli sawlly ciiii'.'li-, _'. il i- cvi.l.'iil iliat spor.' inf('.';i.in .if tin- c.ico.nis lia.l lik.'ii pla.'.'. •>!! no ..('casioii I ..I .serve I tlie infection of a.lults; they'll.'! rapi ll\' I'Ut I'emain.'il iininfecti'il. ;i Til.' funt;u- /.'•■.in.i /'i/'/i.'W'i i> .'apal.le of vefietatini; saprohpy- li.ally t'..r a ..iiiM.lt'lal.l.' leli^h of time, provi.le.l Mlllicii'lit moislui.' is a\ ailalile The .'.'ii.lil ion- iin.ler which this mode of life was ol)serve.l wcie el"-.' to natural .■.in.litioii>. 1 Ouim; l.i thi- saprophyti.' nuxle of lifi- there reniain.s littl. d.iiil't tiiat the piipat ini; larva' of the larch sawfly infect themselves when taking; to the jn'ounl Uf th.' lar.h stwil\ takes plai'c in nature. III. 1 ha\.' t.i reconl some -ihservatioiis on another experiment umli't- takeli to .li.M.'Mr whether it i< po-sil'le t.i infect larch sawlly a.lult> aiii cocoons with spor.'s oi IsonH from i>ure lulliires. Kor this piirpiw ft Hat (rlass .lish contaiiiiii'_' Siihuiiiunn was sterilized on three successiv (lavs in an hot air sterilizer. Althoiitrh the moss hecam.- I.r.iwn in .'oloir (■it;«i«(iw| I'AKAHITISM OK ISAHU KAHIMWA M it Htili rntniniMl HiiliKfiutorily iiii>iHt(irf» in'!< tititt hml lH><>n |iroc|iii'i>il in a pure niliurn of Ixtria. Tho liviiiR lulultH liixt all ilir 'tcr tliriit iiiiy« and none iif tliow (II) (>iniT>finji; fritni tliu cofooim i. .rucUnl ihi- fiiiiKouit ilisciifK". Aftf-r 21 (lavH iid nioit? ailultH cnitTgnl, althouK)) Vi >'|M'(l tin- lypical Isarin aiitl the nii)M al.-o Ih-vmii to ix' I'DvtTfd with niitntTou.-i Isnria colonii'!*. 'I'lii.-* I'xpi'riniont niiitirni* my other ol>M«rvatif)nH and ai«) indicati's that the ili«'aM«> may 1m' iirtilicially intnxhicod evi'n at hi) Into a Maff' in the din-tdopnient of till' lari'h .lawdy. InfiM'tion takes plai'o in nature, no doubt, much earliiT. Although none of my experinietits were made utnler wtrictly natural conditions; that in to r'ay in the open air, yet the oliservation that the fun;:ui< Isnrin is repularly ff)und year after year under larrh trees, when iiiiii' it has been fo\in'l, may indicate that the results obtained really ilo-cly show what take> place in nature. In conclusion, I may say that in Imiria fntinom we possess one ccrt.iin factor, by which the increase of the Ian h sawlly may be con- trolled. Whether it is necessary to resort to these mean^ in the face of the every year increasing' nunitwr of in.sect parasitized larch sawlly cticcions — is somewhat doubtful. I ;