Agrochemical and weed influences on Neoseiulus californicus predation in soybean

The olfactory system is one of the primary decision-making mechanisms in arthropod foraging. Plants emit volatile compounds when attacked by herbivores, which can directly influence predator foraging. Given the diversity of agrochemicals used in soybean cultivation, it is necessary to investigate their possible effects indirect on natural enemies. In this study, the olfactory responses of the predatory mite Neoseiulus californicus were evaluated in soybean plants infested by Tetranychus urticae in the presence of the fungicides Strobilurin and Triazole, the herbicide Glyphosate, and the invasive plant "hairy fleabane" (Conyza bonariensis). The assays were conducted in the laboratory using a Y-tube olfactometer, where the following treatments were evaluated: clean soybean × soybean + T. urticae; soybean + T. urticae × soybean + T. urticae + "hairy fleabane"; soybean + T. urticae × soybean + T. urticae + herbicide; soybean + T. urticae × soybean + T. urticae + fungicide. N. californicus prefers soybean plants infested with T. urticae. In treatments with the application of the fungicides, the herbicide, and the presence of the weed, N. californicus equally preferred plants infested with T. urticae. It is concluded that the foraging behavior of N. californicus is not influenced by the presence of the fungicides (Strobilurin and Triazole), the herbicide (Glyphosate), or "hairy fleabane" (Conyza bonariensis). Our results demonstrate that N. californicus is capable of locating T. urticae-infested plants in the presence of odors commonly found in conventional agricultural systems in soybean crops.