RESPONSE OF Bemisia tabaci Genn TO THE ASSOCIATION TOMATO−AROMATIC PLANT

The silverleaf whitefly (Bemisia tabaci) is the most harmful pest for vegetables in tropical zones. One alternative for its ecological management is the use of repellent aromatic plants. The hypothesis of this study is that the aromatic plants that diminish the attraction of B. tabaci to tomato have the capacity to prevent the infestation of this pest in the tomato crop when an intercropping system of tomato-aromatic plant is established. The objective of this study was to evaluate by means of the technique of olfactometry, the response of B. tabaci to the volatiles emitted by the crushed leaves of tomato and by the combination tomato + aromatic plant. The aromatic plants with highest activity in the olfactometry tests were intercropped in a tomato crop in the field. In the bioassays of olfactometry, a significant decrease was observed in the attraction of B. tabaci to crushed leaves of tomato + some aromatic plants compared with the attraction to tomato alone. The repellence indices (IR) showed that the aromatics Lavandula angustifolia Mill. (IR, 0.1), Petiveria alliacea L. (IR, 0.48), Petroselinum crispum Mill. (IR, 0.28) and Thymus vulgaris (IR, 0.5) had the greatest effect as repellent of adults. By integrating these aromatic species through intercropping in the tomato field crop, no significant difference was observed in the population density of eggs and adults of B. tabaci in the tomato foliage in regard to what was observed in the control (only tomato). The incidence and severity of viral symptoms did not decrease from the presence of the aromatic species intercropped in the tomato crop.