Botanical Pesticides: Role of Ricinus communis in Managing Bactrocera zonata (Tephritidae: Diptera)

Abstract

The melon fruit fly, Bactrocera zonata (Coquillett) (Diptera: Tephritidae), is a notorious pest, posing a significant threat to a wide range of fruits and vegetables, leading to substantial agricultural losses worldwide. With growing concerns over chemical pesticide resistance and environmental safety, plant-based insecticides have emerged as eco-friendly and economically sustainable alternatives. In this context, the present study delves into the insecticidal potential of Ricinus communis extracts against B. zonata. The crude extract of R. communis was systematically fractionated using a series of organic solvents with increasing polarities. The fraction demonstrating the highest insecticidal activity was further purified for the isolation of bioactive compounds, employing advanced chromatographic techniques such as Column Chromatography, coupled with state-of-the-art analytical methods including Gas Chromatography-Mass Spectrometry (GC-MS) and Fourier Transform Infrared Spectroscopy (FTIR). Bioassays were conducted on B. zonata using the crude extract and its fractions in n-hexane, methanol, and ethyl acetate. Among the isolated compounds, 11,14,17-Eicosatrienoic acid was identified in both the methanol and ethyl acetate fractions. This compound exhibited remarkable insecticidal efficacy, with an LC50 value of 1.36%, a linearity of R2 = 0.64, and a statistically significant probability (p < 0.01). Particularly, 11,14,17-Eicosatrienoic acid emerged as the most potent bioactive agent against B. zonata highlighting its potential as a natural insecticide. These findings underscore the potential of R. communis as a valuable source of bioactive compounds for the sustainable management of B. cucurbitae. This study not only broadens the scope of plant-based pest control strategies but also opens avenues for further exploration of natural compounds in integrated pest management.