Subletalidade da abamectina sob diferentes regimes térmicos em fêmeas de Tetranychus urticae Koch (Trombidiformes: Tetranychidae)

Abstract

Tetranychus urticae Koch is a mite pest of economic importance in agriculture. The population dynamics of this pest are strongly influenced by abiotic factors, such as temperature, which, in addition to affecting development and reproduction, can interfere with susceptibility to acaricides. Therefore, this study aimed to evaluate the effect of combining different thermal regimes on the susceptibility of T. urticae females to a subdose of abamectin, assessing survival and reproduction parameters. The experiment was conducted in a controlled environment, using mated females up to 48 hours old, subjected to different thermal regimes (25 °C constant and 25 °C with a peak of 30 °C for 2 hours) with or without a subdose of abamectin (10% of the dose recommended in the label), on day zero (d0) or on day five (d5). The parameters evaluated were: survival, fecundity, and egg viability. Female survival was not influenced by temperature regimes, regardless of acaricide exposure. However, significant sublethal effects were observed, with reduced fecundity and egg viability, mainly when application occurred immediately (d0) and under peak temperature regimes. However, in late application (d5), survival was similar to the treatment without application, indicating a possible increase in tolerance to the chemical. Therefore, for greater robustness of the results, it is necessary to expand this research by simulating other temperature ranges, populations previously adapted to temperature variations, and evaluating population growth parameters