Amblydromalus limonicus (Acari: Phytoseiidae) as a biocontrol agent: literature review and new findings

Amblydromalus limonicus (Acari: Phytoseiidae) was described in 1956 from citrus in California; its distribution range covers North and South America, Australia and New Zealand. It first caught the attention of biocontrol workers in the 1960s as natural enemy of the spider mites Oligonychus punicae and Tetranychus cinnabarinus in avocados and other fruit trees. In laboratory studies, A. limonicus developed into adults and laid eggs on several species of mites, thrips, whiteflies and scale insects, as well as on pollen. Interest into A. limonicus re-emerged in the early 1990s after the western flower thrips (WFT, Frankliniella occidentalis) had spread nearly all over the world. It was collected during surveys for WFT biocontrol agents in New Zealand and Australia. Laboratory and semi-field experiments in the Netherlands and Australia showed that A. limonicus was a very promising candidate for biological control of WFT in several greenhouse crops. However, it was not possible to establish a commercially viable mass rearing system. At around the same time A. limonicus was also identified in surveys in South America for classical biocontrol agents for the cassava green mite (Mononychellus tanajoa) in Africa. Detailed taxonomic research showed, however, that the mites collected in these surveys were a closely related, undescribed species that was given the name Amblydromalus manihoti in 1994. Recently, a mass production system for A. limonicus was developed and the mite became commercially available in January 2012. With the material from this mass production system, more semi-field and field trials could be conducted. Results showed that A. limonicus is also an excellent biocontrol agent for greenhouse whiteflies (Trialeurodes vaporariorum) in various greenhouse crops including roses, cucumbers and strawberries. As this predatory mite originates from more temperate areas, it is a good complement to Amblyseius swirskii, which is currently the most frequently used phytoseiid in thrips and whitefly control, and Transeius montdorensis, which also recently came on the market. Both species originate from sub-tropical regions and have a higher optimum temperature than A. limonicus.