EFFECT OF ESSENTIAL OIL AND PYROLIGNEOUS EXTRACT ON Bemisia Tabaci IN CASSAVA CROPS

Abstract

The whitefly is a major pest of cassava crops, causing damage by sucking sap, reducing photosynthetic area, and impairing plant development. This study aimed to evaluate the insecticidal activity of two formulations, designated D1 and D5, composed of essential oils and pyroligneous extract, against Bemisia tabaci. Concentrations of 50%, 5%, 0.5%, 0.05%, 0.005%, and 0.0005% were tested. Leaf fragments from the BRS 399 cultivar were immersed in the solutions for five seconds, air-dried for five minutes, and then placed in bioassay chambers containing approximately 50 insects. Mortality was assessed after 24 hours. Data were subjected to analysis of variance, and means were compared using Tukey's test at a 5% probability level. A Probit regression model was also fitted to estimate the median lethal concentration. The tested concentrations significantly influenced insect mortality. The highest mortality rates were observed at concentrations of 50% and 5%, reaching 98.0% and 95.6% for D1, and 97.2% and 94.8% for D5, respectively. The estimated LC₅₀ values were 0.04409% for D1 and 0.03336% for D5, corresponding to 0.441 μL mL⁻¹ for D1 and 0.334 μL mL⁻¹ for D5. The formulations exhibited high insecticidal activity and a concentration-dependent response, demonstrating potential for the development of natural products for whitefly management. Field studies are necessary to evaluate phytotoxicity, persistence, and effects on non-target organisms.