Alternative food sources for Amblydromella caudiglans (Phytoseiidae) and effects on predation

Authors: Moretti, Erica; Jones, Camden; Schmidt, Rebecca

Submitted to: Experimental and Applied Acarology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/23/2022
Publication Date: 12/12/2022
Citation: Moretti, E.A., Jones, C.B., Schmidt-Jeffris, R.A. 2022. Alternative food sources for Amblydromella caudiglans (Phytoseiidae) and effects on predation. Experimental and Applied Acarology. 89:29-44. https://doi.org/10.1007/s10493-022-00767-y.
DOI: https://doi.org/10.1007/s10493-022-00767-y

Interpretive Summary: Predator mites are important for pest control in orchards. When pest numbers are low and predator mites do not have prey to consume, their populations can decrease. One way to retain predatory mites when prey are scarce is to provide alternative food that the predators can consume in the absence of prey. Researchers at the USDA-ARS in Wapato, WA and Washington State University performed laboratory studies to determine how a predatory mite performed when offered alternative food sources. Pear and cattail pollen helped the mite lay more eggs and did not distract from its ability to consume pest mites. Researchers can use these results to create programs that help growers conserve their predator mites, reducing the need for pesticides.

Technical Abstract: The addition of supplemental food sources for natural enemies is a growing component of conservation and augmentative bio-control. Supplemental foods can be used to retain natural enemies when prey are scarce and to promote survival, fecundity, longevity, and development of natural enemy populations, especially generalist natural enemies. Amblydromella caudiglans (Schuster) is one of the most abundant predatory mites found in commercial apple orchards in Washington and contributes to spider mite control. However, because its widespread presence in commercial apple orchards was only recently discovered, how supplementary food sources affect its performance is unknown. In laboratory studies, we evaluated the performance (fecundity, retention, prey consumption) of the generalist phytoseiid A. caudiglans on commercially-available supplemental food sources, including factitious prey (Ephestia eggs and Artemia brine shrimp cysts), and pollens of apple, pear, and cattail. We determined that A. caudiglans will not consume Ephestia eggs and performs best on cattail and pear pollens. Combinations of food sources did not enhance the performance of this predator compared to the best performing single-sources. The presence of alternative food sources did not decrease A. caudiglans predation of two-spotted spider mite nymphs, except for Artemia brine shrimp cysts, which had a substantial handling time. These results lay the groundwork for identifying a way to promote and retain this natural enemy in tree fruit cropping systems through the use of food resource applications or floral plantings.