Location: European Biological Control Laboratory
Project Number: 0212-30400-001-007-R
Project Type: Reimbursable Cooperative Agreement
Start Date: Feb 18, 2026
End Date: Feb 17, 2027
Objective:
This project will develop a classical biological control program for the diamondback moth (DBM), Plutella xylostella (Lepidoptera: Plutellidae), an invasive pest with old-world origins that attacks a variety of cole crops (e.g., kale, broccoli, cauliflower) in the family
Brassicaceae.
The specific objectives for the FY25 phase of the project include (1) collecting and rearing non-target plutellid moth species from the southwestern U.S. and (2) conducting host specificity testing of D. semiclausum in collaboration with USDA-EBCL in Montpellier,
France. This project will generate critical information needed for the Environmental Assessment that will accompany a future USDA-APHIS field-release permit request for D. semiclausum. Project results will also be disseminated to stakeholders through extension efforts, including trade magazines and grower meetings in California.
Approach:
Currently, the family Plutellidae includes approximately 150 known species in the world, with 15 species, in three genera, recorded in the Nearctic region, i.e., Eidophasia (3 species), Plutella (7 species), and Rhigognostis (5 species). The initial set of non-target plutellid species from the U.S. evaluated by CDFA will include E. vanella (on Vicia sp. and Osmorhiza sp.), E. dammersi (on Cleome sp.), and R. interrupta (unknown host plant) from California along with P, armoraciae (on Armoracia spp.) and P. porrectella (on
Hesperis matronalis).
EBCL and CDFA will coordinate the collection of non-target plutellids (larvae/adults) to establish laboratory colonies and develop individual species rearing protocols. Morphology and DNA-based methods will be used to confirm species identity. USDA-EBCL will provide supplemental shipments of D. semiclausum from France, conduct local collections of European Plutellids and examine labels of D. semiclausum specimens deposited in museum collections in Europe (e.g., Natural History Museum of London, National Museum of Natural History in France) to obtain further insight on the historical ecological host range of the parasitoid.
Non-target plutellids will be offered to experimental female D. semiclausum in a series of two-tiered exposure studies, consisting of no-choice and choice tests, to determine the physiological and ecological host range of the parasitoid.