Location: Beneficial Insects Introduction Research Unit
Project Number: 8010-22000-031-114-I
Project Type: Interagency Reimbursable Agreement
Start Date: Jun 1, 2025
End Date: Nov 30, 2026
Objective:
Objective 1 – Field release of Ganaspis kimorum in mid-Atlantic states
Objective 2 – Evaluations of factors influencing the efficacy and establishment of G. kimorum and Leptopilina japonica
Objective 3 – Evaluations of factors influencing the overwintering survival of G. kimorum
Approach:
Objective 1: Wasps are produced at BIIRU and shipped to cooperators monthly for release. We will monitor the parasitoid’s establishment and impact in all previously released locations in Delaware through collections of various host fruits from early June to late early November. Fruits will be collected in the area within a 300 m radius of the previous release sites and collected fruit will be held in the lab the emergence of flies or wasps to determine the parasitism. To determine the seasonality as well as overwintering survival of the released G. kimorum, we will set-up SWD lures from May to November at one previous release location in Delaware. Traps will be checked once per week. All collected parasitoids and SWD from traps or fruits will be preserved in 95% alcohol for later identifications.
Objective 2: 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). Tested host plants (ripen period in the temporal order of availability) will include black mulberry, wine raspberry, blackberry, black raspberry, black cherry, Autumn olive Elaeagnus umbellate, American pokeweed Phytolacca americana and bush honeysuckle Lonicera maackii. There will be three treatments, i.e., two infested fruit are exposed to 2 female LJ alone, 2 GK alone or one LJ + one GK for 2 days. Each test for each fruit species and parasitoid species will have 25 replicates. Successful parasitism and outcomes of interspecific competition between the two parasitoid species on different fruit species will be determined.
Objective 3: To determine (1) when the parasitoid will cease oviposition activities in late fall season in the field, and (2) when the parasitoid enters diapause and emerge in the spring post-diapause, the experiment will be conducted in field at one previously release location in Delaware, respectively. There will be totally six field exposures from September to November. For each field set-up date, all infested blueberries by SWD will be prepared 2 days before the field set-up at the lab. At the field site, a large metal cage will be used for all parasitoid exposures and keeping all exposed host fruits during the diapause experiment. On each field set-up day, one mated female wasp will be released into each vial containing two infested berries for one week. There will be 40 vials with parasitoid exposure and 10 vials without exposed to the parasitoid. After the wasps are removed, the vials will be placed into a humidity box to prevent desiccation of diapausing parasitoids in the metal cage. All vials will be checked once every 1-4 weeks (depending on the months) to record emerging flies and wasps until all emergence has ceased in June or July. For each set-up date, 5 vials will be examined, and all fly larvae/puparia will be dissected in late November and March to determine the survival of parasitoids.