Insecticidal and Repellent Activities of Solanum torvum (Sw.) Leaf Extract against Stored Grain Pest, Callosobruchus maculatus (F.) (Coleoptera: Bruchidae)

Abstract Objectives Pesticides are harmful to nature and therefore they are considered to be poisonous to the world. They have adverse effects on human health that include acute toxicity, cancer and endocrine systems, etc. Plants are a good alternative natural source for considering the negative impacts of conventional pesticides. Plant extracts are traditionally used to manage the insects. Methods In the present study, the crude leaf extract of Solanum torvum (Sw.) was investigated for their preliminary phytochemical screening and their ability to protect the stored green grams from Callosobruchus maculatus (F.) adult infestation. The Solanum torvum (Sw.) ethyl acetate leaf extract was exhibited strong contact toxicity and repellent activity against Callosobruchus maculatus (F.) adult. The toxicity was significantly improved while extended treatment times and concentrations of Solanum torvum (Sw.). Results The mean percentage of ethyl acetate leaf extract repellent value was reached 82% at the dose of 1500 ppm/cm2 after 1 hour, followed by methanol (52%) and hexane (28%) leaf extract. The mortality was reached over the ethyl acetate leaf extract nearly 98% at the dose of 900 µg/cm2 after 72 hours, followed by methanol (70%) and hexane (48%) leaf extract. Contact toxicity value of Solanum torvum (Sw.) leaf extract LC50 at 72 hours interval was observed at 393.271µg/mL, 632.338 µg/mL and 894.333 µg/mL for ethyl acetate, methanolic and hexane extract respectively against Callosobruchus maculatus (F.) adult. Conclusion Thus the present study, Solanum torvum (Sw.) leaf extract could be useful for integrated pest management of Callosobruchus maculatus (F.) adult. The ethyl acetate leaf extract was shown good repellent and contact toxicity effect, followed by methanol and hexane extract. This method of natural plant extract can be used to control pests, alternate against the chemical insecticide.