Location: Beneficial Insects Introduction Research Unit
Project Number: 8010-30400-001-039-I
Project Type: Interagency Reimbursable Agreement
Start Date: Jun 1, 2026
End Date: Nov 30, 2027
Objective:
Our main goal is to establish the introduced parasitoid (G. kimorum), monitor the impacts of released G. kimorum and adventive L. japonica on SWD, and understand some key ecological factors that might affect the establishment and efficiency of these two key parasitoids in the mid-Atlantic region.
Objective 1 – Field release and monitoring of G. kimorum in mid-Atlantic states (all cooperators)
Objective 2 – Evaluating factors influencing the efficacy and establishment of G. kimorum and L. japonica (BIIRU)
Objective 3 – Overwintering survival of G. kimorum (BIIRU and University of Maryland)
Approach:
Objective 1 –Field release of G. kimorum in DE, MD and PA be conducted by cooperators in each state. We will mass-produce this parasitoid at BIIRU and ship them to the cooperators monthly for release. We will also monitor the parasitoid’s establishment and impact (parasitism) and document any parasitoid species associated with SWD and related frugivorous Drosophila through fruit samplings in all four previously released locations in Delaware. At each location, we will collect various suspected host fruits in a temporal sequence of fruit ripening throughout the fruit seasons, i.e. from early June to late early November. These fruit samplings will confirm if the parasitoid has successfully overwintered in this region and potential dispersal, and levels of parasitism. We will also set up SWD lures trap from May to November at one previous release location in Delaware.
Objective 2 – All research for this objective will be conducted at BIIRU. To quantify potential effect of different host fruits on the efficiency of the larval SWD parasitoids G. kimorum and L. japonica, we will collect and test the most common fruits available throughout the fruit seasons in the DE area for their suitability as hosts for SWD and their effects on the levels of parasitism by G. kimorum (GK) and L. japonica (LJ). For each fruit species, one set of 20 fruits will be kept individually to monitor the survival, developmental time, and body size pf SWD pupae. Another set of fruit will be used to test parasitism when the larvae are 2-3 days old. There will be three treatments: (1) fruit are exposed to 2 female LJ alone; (2) fruit are exposed to 2 GK alone; and (3) fruit are exposed to one LJ + one GK. Successful parasitism and outcomes of interspecific competition between the two parasitoid species on different fruit species will be determined.
Objective 3 – This research will be conducted at one release site in Delaware (by BIIRU) and another release site in Maryland (by cooperators from University of Maryland). The major objectives are to determine (1) if G. kimorum (GK) could survive the winter in this region; (2) when will the parasitoid enter diapause and emerge in the spring; and (3) whether the parasitoid can still attack SWD in October in the field and whether the diapause might be induced under the field conditions at early or late parasitoid stages. There will be three field set-up dates in early, middle, and late October, respectively. For each set-up date, there will be five treatments: (1) One GK female is exposed to two infested berries in a vial directly in a field metal screen cage and the cage will be placed at a wooded edge; (2) vials containing 2 exposed berries with young GK larvae (0-3 days old) placed in the field cage; (3) vials containing two exposed berries with young GK larvae buried in soil pot near the field cage; (4) vials containing two exposed berries with mature GK larvae (10-13 days old) placed inside the field cage; and (5) vials containing two exposed berries with mature GK larvae buried in soil pot near the field cage. All treatments will be checked regularly from October to July or until all emergence has ceased.