Yael Argov, Martin Berkeley, Miriam Zilberstein, Mickey Noy, Yehonatan Izhar, Jonathan Abrahams, Moshe Coll

Oligonychus perseae was first discovered in Israel on avocado trees in the autumn of 2001; by 2004 it spread to most of the important avocado growing regions. While field monitoring for persea mite we observed Euseius scutalis (Phytoseiidae) feeding on O. perseae within torn nests and outside of the nests. Subsequently, laboratory studies were performed to evaluate the efficacy of this predator. To improve persea mite control, the exotic predatory mite Neoseiulus californicus was released in 2004 and 2005. To determine whether other generalist predators can feed upon and tear the nests of persea mite, insect and arachnid predators were collected from avocado trees using a beating tray technique placed individually on newly infested leaf discs and monitored for several days. Although E. scutalis reduced adult persea mite populations in the lab (on leaf discs) with or without torn nests, egg predation was improved by tearing the nests. Seasonal CMDs following N. californicus releases were reduced by 30%, but leaf damage was still considerable and similar to control trees. Furthermore Phytoseiid predators recovered from all release plots were mostly of the species E. scutalis ranging from 78-95%. In our nochoice bioassays on leaf discs we observed nest tearing and predation by green lace wing Chrysoperla carnea, dusty wing Conwentzia sp. and others. Developing methods for augmentation and conservation of E. scutalis and nest-tearing predators may prove valuable for enhancing persea mite control.