Botanical Pesticide and Insect Pests

In the past decades, apart from the pyrethrum which has attained international and commercial acclaim due to its high effectiveness and broad spectrum insecticidal activity (repels and kills insects depending on concentration) very few natural insecticides have been developed of particular economic significance among the plants in common use today is the tropical plant Azadirachta indica, popularly known as the neem tree. In India as well as in Nigeria the plant is effectively used to control over 25 different species of insect pests. The activity has been associated with the presence of azadirachtin, which is said to be highest in the kernel than in the leaves and other tissues of the plant. The effectiveness of nine insecticidal species of Chineese origin has been compared with synthetic insecticides against 40 species of insects. Three of the plants Milletia pachycarpa Benth, Trpterygium Forrestii Loes and Rhododendron molle G. Don were studied in detail. The finely ground powder when applied as spray in suspension or as dust were highly active against aphids, pentatomids and leaf-beetles as well as against caterpillars, body lice and plant lice.