The cut ends of hemlock branches infested with hemlock woolly adelgid (Adelges tsugae) were treated by being placed in dilutions of imidacloprid and water for 10 days at 14:12ºC (D:N). The two specialist predators Laricobius nigrinus and Sasajiscymnus tsugae were fed A. tsugae from the treated branches. Treatments with L. nigrinus were held at 4:2º C (D:N) and 12:9º C (D:N), while S. tsugae were held at 12:9ºC (D:N) and 20:18º C (D:N). Predators were observed daily for 20 days, with each beetle examined under magnification for uncoordinated movements, tremors, spasms, paralysis, or other typical signs of neo-nicotinoid poisoning. Both beetle species portrayed a positive dose dependant response, with increasing mortality and poisoning symptoms as imidacloprid concentrations increased and as time progressed. Responses also differed between temperatures, with increased mortality at the higher temperatures. Possible non-target impacts of systemic chemical control of A. tsugae are discussed.