Department of Bio-Sciences, Himachal Pradesh University, Summer Hill, Shimla-171 005, Himachal Pradesh (India).
*Present Address: Division of Entomology & Nematology, Central Potato Research Institute, Shimla-171 001 (H.P.)(India).
Efficacy of granular and foliar systemic insecticides was evaluated in field-cum-laboratory experiments consecutlvely for two years against the green peach aphid, Myzus persicae (Sulzer) infesting potato crop under long-day and rain-fed conditions at Shimla. Application of granular systemic insecticides, viz., phorate, aldicarb, disulfoton and carbofuran @ 1.5 and 2.0 kg a.i./ha, either in full at plantlng or in two equal splits (half at planting + half at earthing), proved practically ineffective against M. persicae damaging potato crop. On the other hand, spraying of crop with systemic insecticides at 0.03 and 0.05% concentrations @ 1250 litres of spraylha was effective in controlling this aphid vector. First spraying with any of the eight foliar systemic insecticides, viz, demeton methyl, dimethoate, thiometon, formothion, monocrotophos, phosphamidon, methamidophos and chiorfenvinphos should be done at 0.03% concentration @ 1000–1250 litres of spray/ha, depending upon the age and canopy of crop, soon after noticing 2–4 aphids/100 compound leaves. Subsequently, 1–3 need-based sprays preferably with demeton-methyl may be given at 7-10-day intervals.
