|Abell, Kristopher - University Of Massachusetts|
|Bauer, Leah - Us Forest Service (FS)|
|Van Driesche, Roy - University Of Massachusetts|
Submitted to: Florida Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/11/2016
Publication Date: 12/15/2016
Citation: Abell, K.J., Bauer, L.S., Duan, J.J., Van Driesche, R.G. 2016. Monitoring the establishment and flight phenology of egg and larval parasitoids of emerald ash borer (Coleoptera: Buprestidae) in Michigan, USA using sentinel eggs and larvae. Florida Entomologist. 99(4):667–672.
Interpretive Summary: Emerald ash borer (EAB) is an important invasive pest of ash (Fraxinus) trees in North America and has currently spread to 25 states in the U.S. since it was first detected here in 2002. Parasitic wasps (or natural enemies) attacking EAB larvae (Tetrastichus planipennisi and Spathius agrili) and eggs (Oobius agrili) were introduced into the United States in 2007 for biological control of EAB. However, monitoring their establishment and seasonal flight activities has been extremely difficult because of the lack of effective non-destructive sampling methods. Using laboratory-produced sentinel logs containing EAB larvae and eggs, scientists from the University of Massachusetts, USDA Forest Service and ARS assessed the establishment, abundance and flight activities of these introduced natural enemies in Michigan. Findings from the study demonstrate that sentinel logs containing EAB larvae or eggs can be effectively used as non-destructive sampling tools to assess the establishment, abundance and flight activities of these parasitic wasps attacking EAB larvae or eggs in the field, and thus can enhance our ability to evaluate the efficacy of current EAB biocontrol programs in the U.S.
Technical Abstract: Emerald ash borer (EAB), Agrilus planipennis Fairmaire, is an important invasive pest of ash (Fraxinus) trees in North America. Two larval parasitoids, Tetrastichus planipennisi Yang and Spathius agrili Yang, and one egg parasitoid, Oobius agrili Zhang and Huang, were introduced into the United States in 2007 as part of a classical biological control program. Field studies to assess the flight phenology of introduced and native EAB parasitoids were conducted in central Michigan from 2011-2013 using sentinel logs. Parasitism rates of sentinel EAB eggs by O. agrili ranged from 0-22% in 2011 and 0-6% in 2012. Flight phenology of O. agrili adults varied between years and discrete generations were not apparent. Rather, O. agrili adults were generally continually present over a three month period each year. Parasitism rates of sentinel EAB larvae by T. planipennisi and the North American native Atanycolus spp. respectively ranged from 0-5% and 33-77% in 2011, 0-69% and 0-27% in 2012, and 0-53% and 0-46% in 2013. Phenology of adult flight of both T. planipennisi and Atanycolus spp. was inconsistent between years. Development of nondestructive methods to determine when stages of EAB suitable for parasitism are present in combination with the use of sentinel logs to observe parasitoid phenology as described here will greatly enhance the ability to evaluate the impacts of parasitoids on emerald ash borer.