Susceptibility Status of Helicoverpa armigera Hub. to some Synthetic Insecticides and Neem Seed Kernel Extract as Influenced by Host Plant Sharma R.P., Yadav R.R Department of Entomology and Agricultural Zoology, Rajendra Agricultural University, Bihar, Samastipur-848 125, India. Online published on 31 October, 2011. Abstract Bioassay studies against Helicoverpa armigera for determining toxicity of endosulfan, monocrotophos, fenvalerate, dimethoate and neem seed kernel extract (NSKE) at different concentrations and exposure period (24 to 72 h) revealed that on pigeonpea fenvalerate registered lower value of LC50 in comparison to other insecticides. Fenvalerate and monocrotophos proved 3.903 and 1.019 times more toxic than endosulfan, respectively, whereas, dimethoate was found less toxic. LT50 value was lowest (42.92 d) and highest (136.83 d) for dimethoate and fenvalerate at 0.08 and 0.005% concentration, respectively, on chickpea. More or less similar trend was also observed on pigonpea. Top Keywords Helicoverpa armigera, susceptibility, pesticides, NSKE, chickpea, pigeonpea. Top |