Field evaluation of Beauveria bassiana efficacy for the control of Tetranychus urticae Koch (Acari: Tetranychidae)

Abstract

Trials with eggplants were conducted to evaluate field efficacy of Beauveria bassiana (Bb) applications against Tetranychus urticae, during spring of 2006 and 2007. In the 2006-Trial, a rate of ca. 0.7×10 12 conidia/ha was sprayed onto plants at intervals. In the 2007-Trial, the rates of ca. 0.8×10 12 and 1.6×10 12 conidia/ha were sprayed at 1- or 2-week intervals. Based on population densities of mites and leaf damage assessed throughout the trial, the Bb sprays with 1- or 2-week interval showed better control than those of 3 or 4weeks. In both trials there was no statistical difference between 1-week and 2-week spray interval for all parameters measured. Furthermore, the higher rate performed significantly better than the lower rate, regardless of the intervals. No interaction was found between the spraying interval and the applied rate. Ultimately, to suppress the population density of T. urticae and prevent the eggplant damage in spring, the higher rate applied at 2-week interval was effective. © 2010 Blackwell Verlag, GmbH.