Pantnagar Journal of Research

Abstract

Bollworm complex of cotton is major yield limiting factor of cotton. In the present study, the larvicidal activity of Dashparni extract were evaluated against the bollworm complex of cotton viz., Helicoverpa armigera and Pectinophora gossypiella using diet bioassay. The ratio of toxicant and diet was standardized. The study was conducted under the controlled laboratory condition with 1%, 2%, 4%, 6%, 8% and 10% concentration and compared with control. The result was presented with values of % mortality on each day. All the tested concentrations had larvicidal activity which were significant over control. The increase in % mortality data showed clear relation with the increase in concentration and increase in duration of the feeding time period within the same concentration. At higher concentration (8% and 10%) the effect of extract on % mortality (91.67%) was at par in case of pink bollworm, however in case of american bollworm at highest concentration (10%) the mortality (45.83%) was significant with rest of the treatments. The LD50 value of Dashparni extract for pink bollworm was calculated as 1.01. The Dashparni extract had proved its effect on growth and development of both the bollworm. However, the field efficacy of the same needs the further experimentation