Improving biological control for a foliar spider mite pest of California grown avocados

Persea mite, Oligonychus perseae Tuttle, Abatiello and Baker (Acari: Tetranychidae), is foliar pest of avocados. Feeding by O. perseae colonies induces premature lead drop and has been linked to yield reduction. We are working to improve the biological control program for O. perseae on California avocados in three ways by: 1) developing a sampling strategy to estimate O. perseae densities that facilitates a synchronized release of the commercially available phytoseiid Neoseiulus californicus during the summer months when O. perseae control is greatly needed, 2) identifying a novel, native predatory mite in California that could be used to develop a conservation biological control program for pest mites on avocados and 3) evaluating the long-term role of native populations of predatory mites in regulating O. perseae population densities using an historical data set. The results of this research have broad implications for strengthening the integrated pest management program for O. perseae for the avocado system in California and abroad and developing similar strategies for mite pests in other agricultural systems.