Stability and Resiliency of Biological Control of the Twospotted Spider Mite (Acari: Tetranychidae) in Hop

Abstract

The twospotted spider mite (Tetranychus urticae Koch) is a common pest in agricultural and ornamental crops. This pest can be controlled by resident predatory arthropods in certain situations. This research quantified the stability and resiliency of established conservation biological control of the twospotted spider mite in hop over a 5-yr period associated with nitrogen fertilization rate and use of a broad-spectrum insecticide. Biological control generally was stable and resilient over a sixfold range of nitrogen fertilization rates, and in only 1 of 5 yr did elevated nitrogen rates significantly affect populations of spider mites. In contrast, one application of the insecticide bifenthrin was associated with disruption of biological control and a severe outbreak of spider mites. The complex of natural enemies suppressed the outbreak during the same year in which bifenthrin was applied, but only after populations of spider mites exceeded levels associated with economic damage. However, in the following year the system returned to an equilibrium state where spider mites were suppressed below economically damaging levels. Therefore, conservation biological control in hop appears stable and robust to factors such as nitrogen fertilization that increase reproductive rates of spider mites but may be sensitive to factors such as nonselective insecticides that are lethal to natural enemies. Conservation biological control can be considered resilient to a single use of a nonselective insecticide in the year following the application, but not within the year of application.

Mechanisms and management of acaricide resistance for Tetranychus urticae in agroecosystems

“…Similarly, high expression of these metabolic genes was also detected in T. urticae populations from peppermint and silage corn fields from central Washington (Adesanya et al 2018b). The application of pyrethroids for managing T. urticae on Washington hops has been discouraged because it has been linked with frequent mite outbreaks (Iskra et al 2019). The explanation for this phenomenon is not yet known, although it has been speculated that pyrethroids may benefit spider mites by killing their natural enemies.…”

Laboratory selection, resistance risk assessment, multi‐resistance, and management of Tetranychus urticae Koch to bifenthrin, bifenazate and cyflumetofen on cowpea

“…Biological control is a method widely used in the IPM and the resistance management of the two spotted spider mites . Neoseiulus barkeri ( N. barkeri Hughes) is a polyphagous predatory mite that feeds on various mites and thrips.…”

Results of the Single Release Efficacy of the Predatory Mite Neoseiulus californicus (McGregor) against the Two-Spotted Spider Mite (Tetranychus urticae Koch) on a Hop Plantation

“…Among the important natural enemies of two-spotted spider mites is the predatory mite Neoseiulus californicus (McGregor) [3], which is otherwise frequently used in vegetable plant protection [4,5]. Although studies exist in the literature on the importance of protective biological control [6] and inoculative release of predatory mites against two-spotted spider mites [7] in hop plantations, the scientific literature provides few data on the inundative release of the predatory mite N. californicus into plantations of this interesting field crop. According to [8], N. californicus was successful against two-spotted spider mites in hop rootstock.…”