Past, Present, and Future: Biological Control of Spider Mites on California-Grown Avocados

This review categorizes the diversity of life-styles in the Phytoseiidae, based primarily on food habits and related biological and morphological traits. The life-styles proposed are as follows: Type I, specialized predators of Tetranychus species represented by the Phytoseiulus species; Type II, selective predators of tetranychid mites (most frequently associated with species that produce dense webbing) represented by Galendromus, some Neoseiulus, and a few Typhlodromus species; Type III, generalist predators represented by some Neoseiulus species and most Typhlodromus and Amblyseius species, as well as species in all other genera about which information is available; Type IV, specialized pollen feeders/generalist predators represented by Euseius species. Consideration is given to the relative importance of each of these types in biological control and pest management programs. Show more

Many carnivorous arthropods use herbivore-induced plant volatiles to locate their prey. These plant volatiles are blends of up to hundreds of compounds. It is often unknown which compounds in such a complex volatile blend represent the signal to the foraging carnivore. We studied the role of methyl salicylate (MeSA) as part of the volatile blend in the foraging behavior of the predatory mite Phytoseiulus persimilis by using a Y-tube olfactometer. MeSA is one of the compounds released by lima bean, infested with Tetranychus urticae--a prey species of the predatory mite. MeSA attracted satiated predatory mites in a dose-dependent way with optimum attraction at a dose of 0.2 microg. Predatory mites did not discriminate between a prey-induced lima bean volatile blend (that contains MeSA) and a prey-induced volatile blend to which an extra amount of synthetic MeSA had been added. However, they preferred a MeSA-containing volatile blend (induced by T. urticae) to an otherwise similar but MeSA-free blend (induced by jasmonic acid). Adding synthetic MeSA to the MeSA-free blend significantly increased the mites' choice for this odor, suggesting an important role for MeSA. This study is a new step toward unraveling the role of herbivore-induced plant volatiles in the foraging behavior of predatory arthropods. Show more