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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Systematic Entomology Laboratory » Research » Research Project #434642

Research Project: Protecting the American Chestnut through Proactive Taxonomy and Phylogenetics of Chestnut Gall Wasps

Location: Systematic Entomology Laboratory

Project Number: 8042-22000-289-01-S
Project Type: Non-Assistance Cooperative Agreement

Start Date: Jun 15, 2018
End Date: Jun 14, 2020

The chestnut gallwasp, Dryocosmus kuriphilus Yasumatsu (Hymenoptera: Cynipoidea), is a notorious invasive pest and has been established into many countries in Asia, Europe, and North America in the past 8 decades. This pest, which disrupts young shoot development and causes enormous decline in fruit yields, is a serious threat to commercial Chinese chestnut (Castanea mollissima Blume), and to restoration efforts of American chestnut (Castanea dentata [Marsh.] Borkh.). Recent studies in China revealed that D. kuriphilus maybe a ‘cryptic species’, and the host-plant range is probably much wider than previous thought. This threat will be compounded in the United States as American chestnut x Chinese chestnut hybrids is being developed for resistance against chestnut blight (Cryphonectria parasitica (Murrill) Barr). In fact, this group of wasps has the potential to reverse the progress made in American chestnut restoration, and the proposed research will help focus the fight on the correct species of gall wasp. To this end it is proposed to establish an identification tool for every species of Dryocosmus which will be encountered in field, and work to document, understand, and identify natural enemies that attack and kill Dryocosmus species.

Next generation sequencing techniques (ultra-conserved elements, or UCE’s) will be used to reconstruct a phylogeny of Dryocosmus species using specimens deposited in the National Insect Collection (Smithsonian Institution) and recently collected, undescribed species from the field. Field surveys will also be conducted in conjunction with researchers in China and Taiwan to collect additional species associated with non-Quercus fagaceous hosts. The phylogeny will be a predictive framework to understand which species may become pestiferous in the United States and pose the greatest threat to American chestnut. The identities of natural enemies associated with Dryocosmus species will also be clarified using UCE’s, providing the necessary tools for future biological control efforts against chestnut gall wasps.