Evaluation of Neem Oil, Neem Cake and Other Non-Edible Oil Cakes Against Rice Pests*

Grefnhouse studies on the efficacy of neem oil showed low acute and persistent toxicity against brown planthopper and green leafhopper. It indicated some degree of feeding deterrency against brown planthopper. However, neem oil exhibited pronounced phytotoxicity even at S per cent concentration. Non-edible oil cakes (Neem, Karanj, Mahua, Undi, Kusum and Sai) showed no acute toxicity to brown planthopper and had no considerable influence on the toxicity of car. bofuran. When applied at normally recommended level (0.1 t/ha), the neem cake did not exhibit slow poisoning effects against brown planthopper nymphs. None of the oil cakes was effective against gall midge. Under field conditions, neem oil treatment could not significantly reduce the stem borer, gall midge and whorl maggot damage. However, relatively higher population of mirid bug predator was obtained in plots treated with neem oil.