Control efficacy of pongam (Pongamia pinnata L.) leaf extract against the turnip aphid Lipaphis pseudobrassicae (Davis) (Hemiptera: Aphididae)

The turnip aphid Lipaphis pseudobrassicae (Davis) is considered a cosmopolitan pest of cruciferous crops. It removes photoassimilates from the crops and is responsible for transmitting a number of plans viruses. Control of the turnip aphid is important in stable production of cruciferous crops. The present study was carried out to determine the efficacy of leaf extract from the pongam tree Pongamia pinnata L. against the turnip aphid. In laboratory tests, pongam leaf extract showed acute toxicity to the turnip aphid; the LC₅₀ values were 0.585%, 0.151% and 0.113% at 24, 48 and 72 hours, respectively. Laboratory observations also indicated that low concentrations of pongam leaf extract caused significant reduction of vitality and fertility of the turnip aphids of the subsequent generation and thus caused an indirect reduction of overall pest numbers in the next generation. Pongam leaf extract has thus nonlethal chronic toxicity. Therefore, pongam leaf extract can be recommended as an organic-based pesticide to manage the turnip aphid.