Insecticidal effects of Stephania japonica L. on pulse beetle (Callosobruchus chinensis L.),rice weevil (Sitophyllus oryzae L.) and Mosquito larvae

Abstract

An insecticide is a substance used to kill insects.They include ovicides and larvicides used against eggs and larvae,respectively.Insecticides are used in agriculture, medicine, industry and by consumers. Insecticides are claimed to be a major factor behind the increase in agricultural 20th century's productivity. Nearly all insecticides have the potential to significantly alter ecosystems; many are toxic to humans; Insecticides can be classified in two major groups as systemic insecticide which have residual or long term activity and contact insecticides, which have no residual activity.Experiments were conducted in the laboratory to study the efficacy of Stephania Japonica L. for the control of rice weevil (Sitophilus oryzae L. ) in the storage, pulse beetle( Callosobruchus chinensis L..) in the storage and larvae of mosquito. The efficacy of Stephania Japonica was assessed on the basis of Screening test,repellent test, grain soak test, direct toxic and surface contact effects of rice & pulse grains.Extracts were made using solvents such as acetone,ethanol and water. The extract was used in three doses at 1 mg, 5 mg and 10 mg. The higher doses of Stephania Japonica L. gave better result. The effect of Staphania Japonica on insecticides of direct toxicity, repellency, grain soak and surface contact effects were found directly proportional to the level of concentration. It was observed from the results that the plant extract had significant repellent and screening effect, surface contact effect, and grain soak effect. Mortality percentage was found to vary among different concentrations of plant extracts. The highest mortality was observed with highest concentrations of Stephenia japonica L.