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Amblyseius fallacis is a North American native generalist predatory mite that feeds on most mites. Unlike other predatory mites, A. fallacis can survive low temperatures and remain in areas with low levels of spider mites; able to feed on an array of pests, especially their eggs, as well as pollen. Best used preventatively.
Adults have tan to light orange, pear-shaped bodies (0.5 mm long), and shiny long legs. Immature predators are cream colored or semi-transparent, and eggs are oval (0.3 mm long).
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A. fallacis is used with greenhouse peppers, field strawberries, raspberries, currants and mint. In BC, Washington, and Oregon, IPM programs for field berry crops are based on using A. fallacis as the primary control for spider mites.
A. fallacis is more resistant to pesticides than most biological controls and can remain in areas with low levels of spider mites by feeding on other prey as well as pollen, making them a good option for prevention. They also feed and reproduce at lower temperatures than many other predator mites (48°-85°F, with a relative humidity over 50%)
- Development from egg to adult takes 7-9 days at 70°F (21°C) to 3 days at 32°C. Adult females lay 1-5 eggs per day, for 26-60 eggs total in their 14-62 day life span. Eggs are oval and twice the size of TSSM eggs. Female A. fallacis feed on 2-16 spider mites per day. Adults enter diapause in response to 14 hours of daylength or less (temperature dependent).
- .1 to .5 mites per sqft depending on pest severity. Fallacis will
usually become established in the crop after one to two introductions, where they remain if mites or pollen are available for food. 7,000 to 10,000 per acre for strawberries and other field crops. Placing higher numbers of predators on the prevailing upwind side of the crop will increase their dispersal.
