Skip to main content
ARS Home » Northeast Area » Newark, Delaware » Beneficial Insects Introduction Research Unit » Research » Publications at this Location » Publication #256060
Title: Field-cage evaluation of parasitism, development, and overwintering of two recently introduced biological control agents of the emerald ash borer

Author
item ULYSHEN, MICHAEL - Michigan State University
item Duan, Jian
item BAUER, LEAH - Forest Service (FS)
item GOULD, JULI - Animal And Plant Health Inspection Service (APHIS)
item Taylor, Philip
item BEAN, DICK - Maryland Department Of Agriculture
item HOKOL, CAROL - Maryland Department Of Agriculture
item VAN DRIESCHE, ROY - University Of Massachusetts

Submitted to: Journal of Insect Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/11/2011
Publication Date: 10/31/2011
Citation: Ulyshen, M., Duan, J.J., Bauer, L.S., Gould, J., Taylor, P.B., Bean, D., Hokol, C., Van Driesche, R. 2011. Field-cage evaluation of parasitism, development, and overwintering of two recently introduced biological control agents of the emerald ash borer. Journal of Insect Science 11:141. Available: insectscience.org/11.141.

Interpretive Summary: We evaluated the abilities of two parasitic wasps (Tetrastichus planipennisi and Spathius agrili), biocontrol agents of the invasive emerald ash borer, to parasitize, develop and overwinter following three late-season releases in Michigan and Maryland, where emerald ash borer has become widely established and causes considerable damage to ash trees. In August, September and October of 2009, we selected five young green ash trees at each location, and caged the two parasitic wasp species in cages attached to each tree trunk, where emerald ash borer larvae had been inserted. The following April, we dissected the caged trunk sections to determine the fate of each emerald ash borer larva and the developmental stages of all recovered progeny of the parasitic wasps. At both locations, the two introduced parasitic wasps were able to parasitize hosts and successfully overwinter (i.e., reach adulthood the following spring). For T. planipennisi, successful parasitism occurred for all caged releases in Maryland, but only for the August and September releases in Michigan. At both locations, percent parasitism by T. planipennisi was higher in August and September than in October. For S. agrili, successful parasitism occurred for all caged releases in Maryland, but only for the August release in Michigan. In Maryland, percent parasitism by S. agrili in August and September was higher than in October. Based on these findings, we recommend not releasing either wasp species at either location after September.

Technical Abstract: Field-cages were used to evaluate the abilities of Tetrastichus planipennisi Yang (Hymenoptera: Eulophidae) and Spathius agrili Yang (Hymenoptera: Braconidae), biocontrol agents of Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), to parasitize, develop and overwinter following three late-season releases at both a northern (Michigan) and a southern (Maryland) location within the current North American range of A. planipennis. In August, September and October of 2009, five young green ash trees were selected at each location. Tetrastichus planipennisi and S. agrili were each randomly assigned to one of two cages attached to each tree, surrounding separate sections of trunk in which late-instar A. planipennis had been inserted. The following April, the caged trunk sections were dissected to determine the fate of each A. planipennis larva and the developmental stages of all recovered parasitoid progeny. At both locations, T. planipennisi and S. agrili were able to parasitize hosts and successfully overwinter (i.e., reach adulthood the following spring). For T. planipennisi, successful parasitism occurred for all caged releases in Maryland, but only for the August and September releases in Michigan. At both locations, percent parasitism by T. planipennisi was higher in August and September than in October. For S. agrili, successful parasitism occurred for all caged releases in Maryland, but only for the August release in Michigan. In Maryland, percent parasitism by S. agrili in August and September was higher than in October. Based on these findings, we recommend not releasing the two introduced parasitoids (T. planipennisi and S. agrili) at either location after September.