Abstract:The seed oil of Melia azedarach and seed oil(Azadirachta indica)were strong antifeedants to the asiatic citrus psyllid(Diaphorina citri Kuwa- yama)as indicated by determining the amount of citrus foliage,labelled with radioactive isotope ~(32)p consumed by the insect under nochoice tests in the laboratory.The 2% seed oil of Milia azedarach gave 88.5% and 72.2% antifeedant effect in 24—30 hours,while the seed oil caused 96.7% antifeedant effect in 48 hours The radioautograph taken with the test psyllids also showed the same result.