BIO EFFICACY OF LEAVES AND FRUITS EXTRACTS OF BITTER GOURD AGAINST SPIRALING WHITEFLY, ALEURODICUS DISPERSUS

Abstract

The spiraling whitefly, Aleurodicus disperses Russell (Hemiptera: Aleyrodidae), is a destructive invasive pest in many parts of the world. Fresh leaves and fruit extracts of Momordica charantia obtained with ethanol and water as solvents were evaluated in the laboratory for their insecticidal effect on adults of the spiraling whitefly at 350, 400, 450, 500 and 550 mg/L. The extracts were applied onto guava leaves to observe the mortality of adults by topical and residual spray methods, and later their effectiveness and to obtain the LT50. Ethanolic leaves extracts were effective and caused 96.67% and 96.33% mortalities within the 20 hours at 550 mg/l concentration by topical and residual spray methods. On the other hands, ethanolic fruit extracts were effective and caused 100% mortality of spiraling whitefly within the 20 hours at 550 mg/l concentration after treatment by both methods. Aqueous leaves extracts were effective and caused 73.33%, 80.00% and 66.66%, 80.00% mortalities within the 20 hours at 550 mg/l concentration by topical and residual spray methods. The ethanol extracts at the two highest concentrations (500 and 550 mg/L) showed highest mortality against spiraling whitefly. The LT50 of the ethanol extracts, calculated through probit analysis, was lower than the LT50 achieved by the aqueous extracts in dose 500 and 550 mg/L. Additionally, the repellency effect of both extracts on adults was determined. The aqueous extracts showed highest mean repellency rate (71%) at the dose of 550 mg/L, respectively and it belongs to the repellency class IV. Therefore, the ethanolic leaves and fruit extracts caused greater mortality than the water extracts at similar concentrations.