Effect of Melia azedarach fruit extract on Trialeurodes vaporariorum in organic crops under greenhouse

PALACIOS S.M.,; CARPINELLA M.C.,; MANGEAUD A.,; VALLADARES G.,; DEFAGÓ M.T.; FERRAYOLI C.G.

BIOPESTICIDES INTERNATIONAL

Koul Research Foundation

Año: 2008 vol. 4 p. 121 - 127

0973-483X

In our search for less hazardous insecticides of plant origin, the repellent effects of fruit extract from Melia azedarach L. against the white fly Trialeurodes vaporariorum were investigated in cucumber and tomato crops under greenhouse conditions. In choice experiments performed on cucumber plants, a significantly lower number of T. vaporariorum per leaf was observed. Whereas the number of flies in plants fumigated weekly with 2% Melia extract decreased by 6.2% from the initial number and maintained this figure throughout the study (21 days), the number of individuals in controls rose by up to 56.9%. The same tests performed on tomato plants revealed the same tendency over periods of approximately 7 days. The day after the first and second fumigation a reduction in the number of individuals by apex of 92.8 and 80.3%, respectively was observed in the treated plants whereas in control plants a low increase corresponding to 11.1 and 25.9% respectively, was detected. In a no-choice assay carried out in tomatoes treated every 5 days with the extract solution, a diminution of 66.5% in T. vaporarorium population was observed after the third treatment. The last application, carried out on day 28 as from the beginning of the experiment, almost completely eradicated the pest from the greenhouse. Analysis and quantification of the main constituents of the fruit extract is also discussed in this work.