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Research Project: Biological Control of Asian Longhorned Beetle

Location: Beneficial Insects Introduction Research Unit

Project Number: 8010-22000-031-059-I
Project Type: Interagency Reimbursable Agreement

Start Date: Jun 1, 2022
End Date: Aug 31, 2023

In the past, we have discovered a few natural enemies of Asian longhorned beetle (ALB) in Asia, but the impact of these natural enemies on ALB is unclear and more extensive surveys and evaluations of these natural enemies are needed. We have also imported one Asian natural enemy discovered during previous surveys. Our goal is to continually discover, import and evaluate Asian natural enemies for biological control of ALB (Objective 1), and (2) systematically evaluate the imported and native natural enemies for the efficiency against ALB and host specificity (Objective 2).

For Objective 1, we will conduct surveys of ALB parasitoids in both natural and urban forests in China and South Korea from June to September 2022 when ALB adults are active, and ALB will either be in the egg stage or young larvae. Surveys will focus on new (previously never surveyed) sites in Jilin and Liaoning (northeast), Zhejiang (central coast), and Kunming (southwest) in China and both the northeastern natural forests and new collection sites in urban Inchon-Seoul and Busan-Ulsan areas in South Korea. We will use sentinel logs infested with live ALB eggs and/or young larvae. To explore possible effect of tree species (bark thickness) on parasitoid diversity, we will use two different tree logs (maple vs. willow) in each collection site. Trees infested by ALB will also be sampled by removing the bark containing fresh ALB oviposition pits at each survey site where we will also deploy sentinel logs. All collected parasitoids will be shipped and/or hand-carry (if travel restriction is left) to BIIRU for rearing and quarantine evaluations. In addition, we will identify all previously collected species and publish previous results on the surveys and identification of new species. For Objective 2, all imported parasitoids will be first reared on ALB at the quarantine facility of BIIRU. Detailed evaluations will focus on Spathius anoplophorae; a laboratory population of this species has been established on ALB at BIIRU. We will investigate some basic aspects of each candidate parasitoid’s biology, behavior, ecology and efficiency. Most importantly, we will evaluate host specificity and potential non-target risk of any efficient parasitoids. Adult beetles of non-target cerambycids will be collected and reared to obtain eggs for non-target tests at BIIRU. We will focus on testing common North American cerambycid beetles infesting major hardwood trees. The BIIRU Lab also maintains several other exotic woodborers such as the citrus longhorned beetle (Anoplophora chinensis) that could also be tested to provide insights into the potential use of candidate Asian parasitoids for the biological control of this closely related pest if it becomes established in the US. Non-target test methods have been developed previously for other similar parasitoids. For Objective 3, we will evaluate one common North American parasitoid Ontsira mellipes for its ability detect and attack ALB larvae in field release trials. We have developed optimal rearing methods for this parasitoid, and obtained federal and state permits for the field trial with parasitoid releases and deployment of ALB infested logs in regulated ALB zones in Worcester, MA. Field release of O. mellipes will be conducted in 6 field sites within the ALB quarantine zone in Worcester (half of these sites will serve as non-release control). We will conduct two releases of O. mellipes ¬and two deployments of ALB sentinel logs each month when ALB larvae could be susceptible to the parasitoids’ attack in the field (June to September). In total, there would be 6 releases of parasitoids and sentinel logs from June to late August 2022.