Insecticidal Activity of Indian Plant Extracts against Nilaparvata lugens (Homoptera: Delphacidae)

Methanol extracts from 84 samples of 49 Indian plant species in 30 families were tested for insecticidal activities against the brown planthopper (Nilaparvata lugens STA^^°L), using a topical application method. The activity varied with both plant species and tissue sampled. At a dose of 0.5μg/female, the following 11 extracts indicated significant insecticidal activity: Adhatoda vasica leaves (100% mortality), Annona squamosa seeds (100%), Nerium indicum stems (100%), Clerodendrum inerme whole plants (90%), Pongamia pinnata seeds (95%), Prosopis chinensis stems (90%), Vitex negundo leaves (90%), Azadirachta indica seeds (89%) and stems (85%), Aegle marmelos leaves (88%), and Madhuca indica seed oil (88%). However, the extract of A. squamosa seeds alone exhibited significant activity (100% mortality) even at 0.25μg/female. As naturally occurring insecticides, these tropical plant-derived materials could be useful as an alternative for synthetic insecticides in management of field populations of N. lugens.