Efficacy of the medicinal plant, Andrographis paniculata (Burm. F.) Wall. against hadda beetle, Henosepilachna vigintioctopunctata (Fabricius) (Coleoptera: Coccinellidae) on bitter gourd

Abstract

The current global trend is towards consumption of food produced using safe and preferably natural plant protection products. Detection of hazardous chemical pesticide residues in foods and increased consumer awareness on food safety has resulted to ban of certain pesticides in agricultural production and plant-based pesticides are gaining popularity in organic agriculture. The disadvantages associated with the misuse and overuses of synthetic pesticides have stirred the need for alternative pest management options. Plants with bioactive compounds have been used to manage different crop pests and human infections with notable success. The importance of botanical pesticides is attributed to their efficacy, biodegradability, varied modes of action, low toxicity as well as availability of source materials. Active compounds sitosterol and stigmasterol isolated from Andrographis paniculata were evaluated for its antifeedant, larvicidal and adulticidal activity against Henosepilachna vigintioctopunctata. Isolated compounds stigmasterol and β-sitosterol were evaluated for their antifeedant activity at 250, 500, 750 and 1000 ppm concentrations against H. vigintioctopunctata. Stigmasterol at 1000 ppm exhibited a higher phagodeterrency of 67.83% than β-sitosterol (55.87%). Stigmasterol exhibited maximum larval mortality of 76.0% at 1000 ppm. Maximum adult mortality of 84.0% at 1000ppm was observed with stigmasterol. Apart from the known compound andrographolide, phytosterols isolated from A. paniculata also exhibited promising pest control activities.