Effect of neem excel on the biology of Dysdercus koenigii

Neem excel 0.15% EC was tested by offering cotton seeds impregnated with 0.02, 0.03 and 0.04% concentrations to 4^th instar of Dysdercus koenigii which revealed that the mortality of the 4^th instar nymphs was almost concentration dependent and longevity of treated surviving nymphs significantly increased. Adult emergence was considerably affected at 0.04% concentration, which caused 63.3% emergence in comparison to 95.0% in control. Pre-mating, pre-oviposilion and oviposition periods were significantly delayed while post-oviposition period was shortened to 91.3 hrs. at 0.04% concentration. Eggs laid by a normal female were 115.6 whereas females derived from 4^th instar nymphs which consumed 0.04 and 0.02% neem excel treated food laid 41.6 and 65.6 eggs, respectively. Fertility was significantly reduced. After hatching, malformed individuals, both nymphs and adults were observed in F-1 generation while the degree of deformation was almost same. However, longevity of F-l individuals both mated as well as unmated males and females decreased considerably in comparison to that of untreated control.