Mechanisms and management of acaricide resistance for Tetranychus urticae in agroecosystems

The two-spotted spider mite, Tetranychus urticae Koch, is a constant threat to sustainable production of numerous economically important crops globally. Management of T. urticae is heavily reliant on the application of synthetic acaricides. However, T. urticae has rapidly developed resistance to most of the acaricides available for its control due to its very broad host plant range, extremely short lifecycle, high fecundity, arrhenotokous parthenogenesis, and overwintering strategy. Despite the recent progress in identifying genetic changes/markers associated with resistance toward some commonly used acaricides for T. urticae, there is still limited studies that select and apply these markers in field populations to guide sustainable pest management strategy design. Temporal and spatial characterization of acaricide-resistant phenotypes and their underlying mechanisms are crucial for the design and implementation of successful and sustainable integrated mite management programs. This review highlights the current acaricide resistance status of field-collected T. urticae populations and the underlying molecular mechanisms of resistance. Our review found that some genetic mutations in target sites and/or overexpression of metabolic genes confer resistance in geographically exclusive populations, while some resistance markers appear to be specific to populations at biogeographical areas. Thus, there is a need for locally based coordinated efforts to understand the mechanisms of resistance present in endemic T. urticae populations. Moreover, we discuss a prospective template for designing an effective acaricide resistance management program within various agroecosystems.