Efficacy and field persistence of some insecticides against the white grub, Holotrichia rustica (burm.) (Scarabaedae: Melolonthinae)

Evaluation of five systemic insecticides against of Holotrichia rustica revealed that monocrotophos and dimethoate, respectively at 0.05% and 0.1% caused 100% mortality within 72 hrs (P=0.001). Lower concentration of imidacloprid (Confidor) 17.8% was least effective with significantly less mortality (50%). Evaluation of the persistence of insecticides revealed that monocrotophos and dimethoate killed 40% beetles even after 10 days. These results are significant for effective management of the white grubs of H. rustica, in teak nurseries.