Spread and phenology of Spathius galinae and Tetrastichus planipennisi, recently introduced for biocontrol of emerald ash borer (Coleoptera: Buprestidae) in the northeastern United States

Emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), is an invasive wood-boring pest of trees (Fraxinus spp.) in the United States. It responsible for catastrophic decline urban and forested ecosystems, resulting millions dollars economic losses. Biological control one most promising management options available to reduce A. spread impact. From 2015 2017, two larval parasitoids from native range planipennis, Spathius galinae Belokobylskij & Strazenac (Hymenoptera: Braconidae) Tetrastichus planipennisi Yang Eulophidae), were released areas New York Connecticut. The purpose this study was measure seasonal phenology these introduced parasitoids. May September 2020, sentinel logs containing EAB larvae deployed naturally occurring infested at each release site 2 km intervals up 14 away site. Logs replaced every weeks parasitization rate recorded. Each month, three area also cut debarked record infestation levels, natural rates, parasitoid phenology. We observed that both S. T. emerged first end early June. Parasitization peaked late July mid-August, with distance producing species throughout summer until mid-September. Both detected sites, greatest sites sampled. Debarked produced similar patterns parasitism. Our results indicate classical biological program initiated several years ago has successfully a self-sustaining population planipennisi, which have been spreading widely attacking borer growing season. These findings strongly suggest future efforts may allow wider temporal windows larger strategic spacing points across geographic regions.