The efficacy of some indigenous medicinal plant extracts for the control of upland rice stem borers in Nigeria

摘要

Field experiments were conducted during the 1999 and 2000 wet seasons at the National Cereal Research Institute, Amakama sub-station, Umuahia, Nigeria to evaluate the efficacy of aqueous and acetone extracts of some indigenous medicinal plants for the control of upland rice stem borers. The treatments consisted of 2.5, 5 and 10% each of aqueous and acetone extracts of seed kernels of neem (Azadirachta indica A. Juss), nutmeg (Monodora myristica (Gaertn.) Dunal, physic-nut (Jatropha curcas. L.), castor-oil (Ricinus communis L.), synthetic insecticide: monocrotophos and the untreated check. The monocrotophos was applied at 400g a.i./ha. The treatments were applied at the tillering stage and at the panicle initiation stage. The results showed that the monocrotophos and a number of the plant seed kernel extract treatments significantly (P<0.05) reduced the % deadhearts and % whiteheads caused by stem borers. The yield of the rice culture in the two years trials were significantly (P< 0.05) higher in monocrotophos treated plants and in a number of the plants extracts treated plants than the control. Comparatively, neem seed and physic-nut seed kernel extracts were superior to the other plant extracts in controlling stem borers and influencing yields of the crop. The results suggest, that aqueous and acetone extracts of neem seed kernel and physic nut seed kernel can be used by upland rice farmers to control stem borers and obtain higher crop yields