Research Project: Effective Biological Control of European Cherry Fruit Fly

Location: European Biological Control Laboratory

Project Number: 0212-30400-001-009-I
Project Type: Interagency Reimbursable Agreement

Start Date: Apr 1, 2026
End Date: Mar 31, 2029

Objective:
Goal: Find ways to enable economically sustainable and effective biological control against European Cherry Fruit Fly (ECFF). Objectives: 1) Establish laboratory populations of promising ECFF parasitoids. 2) Enable year-round mass rearing of ECFF parasitoids. 3) Explore the application of augmentoria for ECFF and other cherry pest biocontrol enhancement.

Approach:
Objective 1: Establish laboratory populations of promising ECFF parasitoids. Research will mainly focus on the three most promising parasitoid species: Utetes magnus, Psyttalia rhagoleticola, and Phygadeuon wiesmanni. Field collections in cultivated cherry orchards as well as on wild Prunus spp. and Lonicera spp. (honeysuckles) will be conducted in Europe and by colleagues in New York State (Cornell University) to determine the natural enemies assemblage of ECFF in different locations of its native and invasive range. Collection sites in Europe will be conducted in the south of France and in Switzerland. Samples of infested fruits will be brought to laboratory and monitored for ECFF and parasitoid emergence. In addition, samples of soil under host trees will be collected and ECFF pupae will be extracted from the soil following established protocols (Hoffmeister 1992). Extracted pupae will be monitored for parasitoid emergence. Parasitoids will be identified via morphological examination and molecular tools. For each site of collection, parasitism rates will be calculated to estimate the impact of natural enemies on ECFF populations. Objective 2: Enable year-round mass rearing of ECFF parasitoids. We will use factitious host, the medfly Ceratitis capitata, which is continuously mass-reared under laboratory conditions around the world, to rear ECFF parasitoids. We will follow the approach that was successfully developed at EBCL for research on another tephritid pest, the olive fruit fly Bactrocera oleae (Chardonnet et al. 2019). Briefly, this method involves rearing C. capitata larvae on an artificial diet, transferring them to the surface of a round polystyrene ball covered by Parafilm, exposing this ball to parasitoids for oviposition, then returning the C. capitata larvae to artificial diet to complete their development and pupate. To stimulate ECFF parasitoids to inspect the ball containing the factitious host larvae, cherries can be attached to the ball during exposure period. Objective 3: Explore the application of augmentoria for ECFF and other cherry pest biocontrol enhancement. Another set of experiments will aim to develop an augmentorium (Klungness et al., n.d.) device adapted to the ECFF system, to provide a refuge for parasitoids during winter months while reducing the number of flies entering orchards during the spring. Developing the specifics of this augmentorium, specifically 1) collection method for pupae post-harvest, and 2) selection of an adequate mesh and design for the augmentorium, will be the second objective of this research project. EBCL has experience in adapting the augmentorium strategy to tephritid pests, including the olive fruit fly Bactrocera oleae (Desurmont et al. 2022). Specifically, different collection methods (sleeve nets, insect cloth, pupation trays) will be compared under controlled and realistic conditions to determine the most cost-effective method to collect ECFF pupae post-harvest. In parallel, experiments will be conducted with different sizes and shapes of mesh material.