THE POTATO MOTH.

Dominion, Volume 6, Issue 1655, 23 January 1913, Page 8

THE POTATO MOTH.

'.'.' •. ■ : ; ; ' ; A'. TRQUBtESOJIE PEST: ,';\ : >•/. -. -.A- paper. on .''The '.. Intensity of the "Life Forms: of- the- Potato Moth" wns contribiiteil to■th6.;.Vustrhliarf;Sciencc Congress by Dr. Stowai/fl. The potato moth,-., ho said, -was'probub'.y ouo.of the. most troiitlesomo .pests' which'ravago, thev potato' crops of the. Commonwealth.-, Protective; methods colnprised-.'thd.steeping of .tubers lii'■■solutcon's--'of'formalin;'., mercuric 'chlor-;-' ule, etc:,treatment Jwitlr lime, and:'mixtures of'lime- nhd 'other substances, and; fumigation with' carbon.; Experiments 'showed: that'.when larvae-infested'.'tubers' were steeped in' solutions'.of formalin'prepared by .mixing 4, ,1,. or. 2 .pints of, : the. compound with' 15-J gallons ;of water, '.it,', required a steep of 21 to ,48 hours' dura-, tion to ensure the' destruction of the invading larva?. . Control: experiments.'.'in which the' infected material ill / water alone ;arid .for .similar■ ■ periods, indicated that this': method of treatment.: was 'nuite:.;as :; eff«ctivo,as ,the steeping: in •solutio'n's'lj'bf formalin. . During the earlier'stages drowning rather .than poisoning'of; the infesting larvae took place..Similarly contacted experiments with isolated larvae", show that these. organisms well'able to' 1 withstand;a steep'of.l to 6 hours', duration in solutions of formalin; of half to 2 hours' duration in a splfitidn'of mercuric chloride .(loz. to 3 gallons of water). V Similar results attended the steeping-of,larvae in an aqueous ;l'i, per cent.'solution of 'copper sulphate;- a;stee'p of 6 hours' duration fails. to,,seal t the fato of the larvae. When tuber 3 'are.'iuimeried./fdr a', period of ;12' hours in asotution. of mercuric chloride (loz.: to 8. water); the treatment was-quite ineffective./: Steeping in aqueous solutions, of 5 per cent, or' 10 per cent. • .sulphuric acid for.-l to 2 hours yielded similar results. /Experimental ;work t directed to'the-'aiin of ascertaining whether, the steeping-of .uninfested. tubers in a solution of mercuric 1 chloride or in suspension of lead-arsenate would' prove effective against infestation showed that their ineans of treatment was quito ineffective. ' In regard to the treatment.of tubers by'stceping, the period of fumigation was-restricted to 48 hours, and the amount 'of fumigation to .lib. to 21b. per 1000 cubic feet; then initially.unsprouta , tubers might be" intermittently ..fumigated 2; 3, and'possibly 4 times without endan-gering-the vitality of the tuber, buds. Tubers subjected to intermittcntfumigation'ahd a subsequent storage ..period, of two to throe months,: 0 n planting had, yielded quite as good crop results as similar hut uhfumigated Rubers...