How to Use Western Predatory Mite
Biocontrol category:
When to use: In the western US, this predator is often naturally present in various crops, especially apples and grapes. Conserving this predator involves avoiding harmful pesticide applications throughout the year. To release, target when spider mite populations are building earlier in the season. Releases do not seem to be able to control outbreaking populations.
Rate: Currently, there are no release rate recommendations based on scientific studies. The necessary rate will likely depend on the current pest mite density and the crop type. Consult with your local extension representative and the insectary to determine which release rate to use.
Maximizing effectiveness: Avoid releasing when temperatures are below freezing; although these predators are cold-tolerant and can survive temperate winters, they will not thrive when suddenly placed into a cold environment. Similarly, they do not appear to be effective during the hottest and driest parts of the year in highly arid environments (e.g., parts of California). Release at first sign that spider mite populations are building and repeat releases as necessary. Consult with your local extension representative and the insectary to maximize effectiveness of this predator. For both naturally present and released predators, avoid making pesticide applications that are known to be harmful (see Conservation).
Pest stage: All life stages of the pest are targeted by this predator.
Mode of action: Predator
Conservation: The primary method for conserving western predatory mites is to avoid or limit harmful pesticide applications when possible. See Compatibility for pesticide selectivity information. The presence of rust mites, especially in apples where they are rarely pests, can greatly aid conservation of western predatory mites, which will feed on rust mites when spider mites are scarce. Pesticides that harm rust mites may reduce populations of predatory mites.
Compatibility: Some, but not all, naturally occurring populations of western predatory mites have developed resistance to a few pesticides, including carbaryl and some pyrethroids. In general, the use of pyrethroids, neonicotinoids, organophosphates, sulfur, fenpyroximate, abamectin, and etoxazole should be avoided or limited. Bifenazate, cyflumetofen, and diamides appear to be mostly harmless to this predator. Many websites provide pesticide compatibility information for western predatory mite and other mite predators (some require a subscription). (Any time you use a pesticide, you must read and follow the label directions and comply with all applicable laws and regulations related to pesticide use. Also be sure that any pesticide used is approved for use in your country and state/province.)
Risk: There is no evidence of harm to human or environmental health.
Commercially available: Yes
