Biorational Pesticides for the Control of Brevipalpus yothersi (Acari: Tenuipalpidae) and Their Compatibility with Predatory Mites

Recently, ornamental plants in urban and unmanaged landscapes were found to be infected with several plant viruses transmitted by Brevipalpus mites. The main purpose of this research was to identify suitable tools for managing Brevipalpus yothersi in these environments by evaluating the efficacy, persistence, and rainfastness of selected biorational pesticides, as well as their compatibility with the predatory mite Amblyseius largoensis. We found that horticultural oils (i.e., petroleum distillates with varying levels of refinement, marketed as mineral or paraffinic oils) and Beauveria bassiana (Strain GHA) suppressed all developmental stages of B. yothersi at levels comparable to spirodiclofen, a commonly used acaricide for controlling B. yothersi. The paraffinic oil provided the best overall performance across the rainfastness, residuality, and greenhouse evaluations. This food-grade horticultural oil is exempt from residue tolerances and could be readily adopted for B. yothersi control in urban landscapes. Paraffinic oil had adverse effects on predatory mites. However, predator populations recovered after paraffinic oil application, and the combined treatment of paraffinic oil + A. largoensis ultimately provided better control than either the predators or the oil alone. When properly applied, horticultural oils provide a practical option for controlling populations of viruliferous Brevipalpus mites in urban and unmanaged landscapes.