Author(s): Umme Habeeba1* and Muniswamy David
One of the synthetic pyrethroid like lambdacyhalothrinis commonly used for pests like aphids, Colorado beetles, thrips, Coleoptera larvae and adults in agricultural crops such as cereals, cotton, potatoes, vegetables etc. In this study a 96hLC50value of lambdacyhalothrinon Cyprinuscarpio by semi-static bioassay renewal method was found. One- eighth (0.2µg/L) of the 96h LC50 (1.62µg/L) were selected as sub lethal concentration. Upper and lower confidence limits at 95% for LC50were 1.783 and 1.435 respectively. Sexually mature common carp (Cyprinuscarpio) of both sexes were exposed to 1/8th(0.2µg/L) of LC50for 1, 5, 10, 15 and 20 days and gonad histomorphology was assessed. Testicular changes in the treated fish include progressive increase in the gaps in the interstitium between lobules and atrophy of the germinal epithelium. The changes pronounced as the days of exposure increased. The ovary also showed significant changes as the days of exposure increased. The changes include broken ovarian follicle, cytolasmic clumping and interfollicular spaces, wrinkled oocytes and atreticoocytes.