• Simmons, Gary A.
  University of Maine
  
• Brown, Harold L.
  Georgetown, Maine
  
• Gibbs, K. Elizabeth
  University of Maine
  

Imidan 1-E was applied to three 600 acre blocks at a rate of 1/2 lb ai/acre, and evaluations were made of its efficacy in spruce budworm control and some non-target impacts.

Percent reduction of budworm larvae after 14 days was only 84% compared to 72% in untreated controls. Considerable current tree foliage was preserved, however, suggesting that Imidan may be a deterrent to larval feeding.

Numbers of singing, male birds decreased significantly in the treated plots while increasing in untreated plots. No dead birds were seen however. Small mammal populations showed no perturbations during the observation period.

Imidan showed no impact on the spruce budworm parasitoids, Apanteles fumiferanae or Glypta fumiferanae. Parasitism rates were higher in larvae surviving spray application than in prespray budworm populations sampled or in unsprayed populations.

No impact was seen in aquatic insect populations in small, swift-running streams, but there was a measurable effect of Imidan in an open, slow-water stream and in a small pond. Certain caddisflies and crustaceans were temporarily eliminated and some fish were killed.