Division of Entomology & Nematology, Central Potato Research Institute, Shimla-171001 (HP)
The findings of a replicated field experiment conducted for four years (1989, 90, 91 & 92) to evalute the relative efficacy of insecticides against white grubs, Holotrichia spp., key-pests of potatoes in north-western hilly regions, revealed that although all the insecticidal treatments were effective in minimising the grub damage, spraying of ridges with chlorpyrifos 20EC thrice each time @ 0.5kg a.i./ha after diluting in 1250 litres of water, registered maximum protection to potatoes. This treatment was respectively followed by the same insecticide sprayed twice, once and granular application of quinalphos 5 G near plants base, just before earthing.
