Abstract:
The relative efficacy of 1 2 contact insecticides to the third and fifth instar
nymphs of the brown plant-hopper Nilaparvata lugens was assessed in the laboratory
by assessing their LC 50 values. These chemicals were found to be equally
effective against both the stages of the pest. Insecticides found most effective
were carbaryl, monocrotophos, quinalphos, fenthion, phosalone, fenitrothion and
dichlorvos. On relative cost basis these may be ranked ascarbaryl, monocrotophos
dichlorvos, phosolone, fenthion, fenitrothion and quinalphos, against third instar
nymphs and carbaryl, monocrotophos, quinalphos, fenitrothton, fenthion, phosalone
and dichlorvos against fifth instar nymphs.
