Efficacy of extracts of Melia azedarach L. callus, leaves and fruits against adults of the sweetpotato whitefly Bemisia tabaci (Horn., Aleyrodidae)

Bioassays with extracts of callus, fruit and leaves of the Chinaberry tree, Melia azedarach L., were performed against adults of Bemisia tabaci (Genna dius). Tissue culture of M. azedarach was carried out in Murashige and Skoo g (MS) medium supplemented with indole butyric acid and benzyl adenine. Fre sh and frozen leaves or fruits and the callus product were extracted in wat er or methanol at a ratio of 1 : 5 (w/v) for 48 h. The aqueous and methanol extracts were applied on tomato plants to determine their effect on B. tab aci adults and their corresponding oviposition and consequent adult emergen ce in comparison with the control, distilled water. Results have shown that extracts of callus and different age classes of M. azedarach leaves and fr uits have shown significant repellent activity of 58.9-67.7% and have signi ficantly decreased the oviposition rate of the insect without affecting the adult whitefly emergence in comparison with the control. Aqueous and metha nol extracts have shown comparable effects against adult whiteflies indicat ing a similar efficacy of the two solvents in extracting the bioactive comp onents of Melia. Extracts of frozen samples were found to be as effective a gainst the pest as fresh samples, thus allowing storage of Melia parts to b e used in case of shortage. This is the first report of the use of M. azeda rach callus against B. tabaci; the AL azedarach callus, leaf and fruit extr acts seem to present a potential source for management of B. tabaci.