FARMING NEWS

Wairarapa Age, Volume XXV, Issue 10713, 31 January 1913, Page 7

FARMING NEWS

THE POTATO MOTH. A paper ou '"lhe Intensity °t the Life Fonns of the Potato Moth - ' was contributed to f!l« Australian Science Congress by J)r Steward. 'J He potato niotlv, ho said, was probably one of the most troublesome pests which ravage the potato crops of the Commonwealth. Protective methods comprised t'lio steeping ol tubers in solut.on.s of formalin, mercuric chloride, etc., treatment with lime and mixtures of lime and other substances, ami fumigation with carbon. hxperiments showed that when larvae-infested tubers were steeped in solutions ol formalin prepared by mixing i,1,0r 2 pint-s of the compound with L> gallons of water it required a steep of 24 to 48 Jiours' duration to ensure the destruction of the invading larvae, {outrol experiments in which the infected t [material was steeped in water alone Land for -similar periods, indicated that this method of treatment was quite as effective as the steeping in solutions of formalin. During the earlier stages drowning rather than poisonin the infested larvae took place. Similarly conducted experiments with isolated larvae show that there organisms wore well able, to withstand a ■steep of 4 to 6 .hours's duration in a solution of mercuric chloride (loz. to 8 gallons of water). Similar- results attended the. steeping of larvae :n an aqueous per cent, solution of copporsulphate; a steep of (> hours duration fails to seal the fate of the larvae. When egg-infested tubers are immersed for a. period el 12 hours in a .solution of mercuric chloride (loz. to S gallons water), the treatment wa« qnite ineffective. Steeping in aqueous solutions of o per cent, or 10 per cent, sulphuric acid for 1 to 2 j hours yielded -similar results. Experimental work directed to the aim nl ascertaining whether the steeping ol uninfected tubers in a solution of nvpreurie chloride or in suspension of leadarsenate would prove cflective. Tn regard to the treatment of tubers bv steeping, the period of fumigation was restricted to 4B hours, and the amount of fumigation tn lib. to 21b. per 1000 euhie feet; then initially unsprouted ' tubers might intermittently fumigat- ! Ed 2.3. and possibly J time* without I endaiigerng the vitalitv of the tuber lmds. Tubers suhiected to intermitt- ' .ent fumigation and a subsequent siorr 1 Viojo period of two to three months, on 'planting had yielded ouite as good j crop results as similar hut unfu.migI <ated tubers.