by Rebecca Schmidt and Elizabeth Beers, published on-line March 2014
(Acari: Phytoseiidae)
Amblyseius andersoni Chant
This predatory mite is found throughout northern hemisphere, including the United States, Canada, Europe, Japan, and India. Plant hosts include, apple, pear, and maple. It is a generalist and will prey on European red mite, twospotted spider mite, Pacific mite, apple rust mite, brown mite, and cyclamen mite. In European orchards, it is considered the most second most important predatory mite (behind T. pyri) for integrated mite management. In addition to mite prey, it can also feed on pollen and thrips.
Reports on the pesticide tolerance of this species are mixed. The general pattern seems to indicate that North American populations tend to exist in unsprayed and lightly sprayed conditions, whereas European populations are considered pesticide tolerant.
Euseius finlandicus (Oudemans)
The Euseius genus of Phytoseiidae contains the most generalist species, as well as specialist pollen-feeders. Euseius finlandicus will feed on spider mites (including European red mite and twospotted spider mite), rust mites, and a variety of pollens. This species occurs virtually worldwide, on a wide variety of plant hosts. This distribution has been attributed to the ability of this predator to reproduce on many different prey species. Euseius finlandicus is considered to be fairly pesticide susceptible. However, its ability to subsist solely on pollen suggests that it has the potential to be an effective biological control agent when pest mites are scarce (essentially preventing outbreaks).
Other species
In addition to A. andersoni, E. finlandicus, G. occidentalis, A. caudiglans, and T. pyri; Metaseiulus citri (Garman & McGregor) and Galendromus flumenis (Chant) have been found in an unsprayed research orchard in Wenatchee, WA. This indicates that these species may be present in abandoned trees in other areas of the state.
Life stages
All stages of these mites look similar to G. occidentalis. Slide mounting is needed to distinguish between species.
Monitoring
Examine the undersurface of leaves where mites are likely to be. Use a leaf-brushing machine to count both pests and predatory mites. Repeat samples at intervals to monitor changes in their relative abundance. Optimum predator-prey ratios have not yet been established for these predators.
References consulted
Abdallah A.A., Zhang Z.-Q., Masters G.J. and McNeill S. 2001. Euseius finlandicus (Acari: Phytoseiidae) as a potential biocontrol agent against Tetranychus urticae (Acari: Tetranychidae): life history and feeding habits on three different types of food. Experimental and Applied Acarology 25: 833-847.
Amano H. and Chant D.A. 1977. Life history and reproduction of two species of predacious mites, Phytoseiulus persimilis Athias-Henriot and Amblyseius andersoni (Chant) (Acarina: Phytoseiidae). Canadian Journal of Zoology 55: 1978-1983.
Blommers L.H.M. 1994. Integrated pest management in European apple orchards. Annual Review of Entomology 39: 213-241.
Collyer E. 1956. Notes on the biology of some predacious mites on fruit trees in south-eastern England. Bulletin of Entomological Research 47: 205-214.
Szabo A., Penzes B., Sipos P., Hegyi T., Hajdu Z. and Marko V. 2013. Pest management systems affect composition but not abundance of phytoseiid mites (Acari: Phytoseiidae) in apple orchards. Experimental and Applied Acarology. doi:10.1007/s10493-013-9752-0.
van der Linden A. 2004. Amblyseius andersoni Chant (Acari: Phytoseiidae), a successful predatory mite on Rosa spp. Communications in applied biological science 69: 157-163.
