Effect of some tropical plant extracts against subterranean termite, Odontotermes wallonensis Wasmann. (Termitidae: Isoptera)

Studies were conducted to evaluate the antitermitic activity of seven tropical plant extracts viz., China berry (Melia azedarach l.), Indian Acalypha (Acalypha indica l.), flamboyant (Delonix regia Raf.), Pungam (Pongamia pinnata l.), Malabar nut (Adathoda vasica l.), Oleander (Neerium oleander l.) and Chaff-flower (Achyranthes aspera l.) against the subterranean termite, Odontotermes wallonensis. All the plant extracts were tested at 10 per cent concentration which differed significantly (p<0.05) from the control and standard (Chlorpyrifos 20 EC @ 0.1%). The aqueous extracts of A. indica, N. oleander and M. azederach caused 78.23, 71.05 and 69.00 per cent mortality, respectively at 48 hours after treatment (HAT). The control resulted in 7.33, per cent mortality, while the standard caused 100 per cent mortality during 48 HAT. In the antifeedant activity test, mean weight of food consumed by termites was lowest in M. azedarach (0.07 g), N. oleander (0.15 g) and P. pinnata (0.16 g) where standard check and control recorded 0.12 and 0.58 g respectively.