Effects of the Ethanol Extracts of Leaves and Branches from Four Species of the Genus Croton on Tetranychus urticae Koch (Acari: Tetranychidae)

Abstract

The two-spotted spider mite Tetranychus urticae is one of the principal agricultural pests, infesting important cultures such as cotton, grapes and tomatoes. In recent years, studies with the objective of using plant extracts as an alternative pest control are being intensified, showing to be a promising alternative and attracting the interest of a growing number of scientists. The present study aimed to evaluate the residual effect of 1% ethanol extracts of leaves and branches of four species of the genus Croton (C. rhamnifolius Kunth, C. sellowii Baill, C. jacobinensis Baillon, C. micans (Baill)) on the spider mite T. urticae. Leaf disks with the mites were immersed for five seconds in the extracts. It could be verified that the leaf extract of C. sellowii caused 69% mortality and the leaf extract of C. Jacobinensis was not toxic to the spider mite. From the experiments it was concluded that the fecundity of the mites was affected and that the extracts were repellent at a concentration of 1%.