Predatory Mites May Help Control Thrips

USDA-Agricultural Research Service (ARS) scientists, along with researchers at the University of Florida are studying two mites, Neoseiulus cucumeris and Amblyseius swirskii, to see if they may be useful for control of chilli thrips in up to 150 crops, including ornamentals.

Research showed that these two predatory mites, which are have been used commercially to combat other pests, significantly reduced the number of thrips. The researchers put 30 adult chilli thrips on ornamental pepper plants in greenhouse and outdoor settings, waited a week for thrips larvae to hatch and, in separate treatments, released 30 mites of each species on the plants. They checked the plants weekly for four weeks. A. swirskii left no more than one thrips insect per leaf. Up to 60 thrips larva were found on leaves of untreated pepper plants. The work was funded in part by the American Floral Endowment and the Floriculture and Nursery Research Initiative.

The chilli thrips feeds on leaves, turns them brown, and kills new growth. Detected in Palm Beach County, Fla. in 2005, it has spread to 24 Florida counties and parts of Texas, damaging roses and other ornamentals in both states. Left unchecked, it could reach west to California and north along the Pacific Coast to Canada, causing losses of up to $3.8 billion annually, according to ARS.

To read more about chilli thrips, visit

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