This thesis, presented in three chapters, focused on evaluating the phenology, density, distribution and parasitism of Asian chestnut gall wasp (ACGW) (Dryocosmus kuriphilus Yasumatsu), as well as the level and persistence of two systemic insecticides in chestnut orchards in southwest Michigan. In chapter one, phenology, density and parasitism of ACGW were monitored in up to nine Michigan chestnut orchards from 2017 to 2019. Phenology was related to cumulative degrees days which provided precise timing recommendations for scouting activities or applying cover spray insecticide applications that target the adult wasp. After cold winter temperatures in 2019, the ACGW population was significantly reduced at all monitored locations. The parasitoid of ACGW is established in Michigan and naturally spreading with ACGW.In chapter two, spread and distribution of ACGW was monitored at both the local and regional scale. Diffusion of ACGW through individual orchards progressed quickly and annual spread across Michigan showed large jump distances. Cold winter temperatures in 2019 halted ACGW spread across the state, suggesting ACGW may face a climatic barrier.In chapter three, imidacloprid and emamectin benzoate residues were assessed in chestnut foliage, catkins and nuts. Both insecticides were occasionally found in catkin samples and rarely found in nut samples. Imidacloprid foliage residues were generally high, but variable. Emamectin benzoate foliage residues varied considerably between two treatment years.
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