Skip to main content
ARS Home » Pacific West Area » Wapato, Washington » Temperate Tree Fruit and Vegetable Research » Research » Publications at this Location » Publication #423104
Research Project: Integrated Approach to Manage the Pest Complex on Temperate Tree Fruits

Location: Temperate Tree Fruit and Vegetable Research

Title: Evaluation of drone and ground releases of Cryptolaemus montrouzieri for mealybug (Pseudococcus maritimus) control in apples

Author
item Moretti, Erica
item Schmidt-Jeffris, Rebecca

Submitted to: Biological Control
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/29/2025
Publication Date: 6/1/2025
Citation: Moretti, E.A., Schmidt-Jeffris, R.A. 2025. Evaluation of drone and ground releases of Cryptolaemus montrouzieri for mealybug (Pseudococcus maritimus) control in apples. Biological Control. 207. Article 105805. https://doi.org/10.1016/j.biocontrol.2025.105805.
DOI: https://doi.org/10.1016/j.biocontrol.2025.105805

Interpretive Summary: Mealybugs can be difficult to control in organic apples due to a lack of effective control options. Some Washington apple growers have tried releases of the commercially-reared ladybeetle, "mealybug destroyers", but are uncertain if these predators are effective for mealybug control. USDA researchers in Wapato, WA investigated whether releases of mealybug destroyers through hand-applications or drone could reduce mealybug abundance in apple orchards. Releases were tested in four trials. Mealybugs were only reduced in one of the trials, where a high rate was used. Mealybug destroyers appear to need very high levels of the pest and specific weather conditions to be effective. Because of their high cost, mealybug destroyers are not currently recommended for pest control in apples, allowing growers to save money and explore other strategies.

Technical Abstract: In apple growing regions of Washington State (USA), mealybug outbreaks are infrequent but can be severe, especially in organic production systems. Because insecticide sprays are ineffective for this pest, management tactics are limited, and alternative approaches that are compatible with organic practices are needed. In four trials (2020-2023), we evaluated releases of mealybug destroyers, Cryptolaeumus montrouzieri Mulsant (Coleoptera: Coccinellidae), for the control of grape mealybug, Pseudococcus maritimus Ehrhorn (Hemiptera: Pseudococcidae), in commercial organic apple orchards. Crytpolaemus montrouzieri are well known for their role in classical biological control of mealybug pests in a variety of cropping systems worldwide, and this is the first report of their use as augmentative biocontrol in apple orchards in the US. Different application types (drone vs hand-releases), timings, life stages (adults vs larvae), and rates were tested. In 2020, early season hand releases at high rates (12,355 /ha) reduced P. maritimus relative to the untreated control, but in subsequent years no efficacy was observed; pest pressure was also lower in these trials. Across all four years of the study, C. montrouzieri adults dispersed rapidly from field sites, especially in drone releases. Further research is needed to assess if larval releases in mealybug “hot spots” can be effective. Based on their propensity for dispersal, high host-density dependence, and expense, releases of adult C. montrouzieri for P. maritimus control in apple are not strongly supported.