- Millers, Imants
The eastern spruce budworm, Chrositoneura fumiferana (Clem.) is one of the most destructive pests of eastern spruce-fir forests. Aerially applied insecticides frequently are used to reduce spruce budworm larval populations and prevent tree mortality. Orthene Forest Spray is one of many insecticides registered with the U.S. Environmental Protection Agency for budworm control. The recommended rate is 2/3 lbs Orthene Forest Spray in 2 qts of water per acre (12% conc. with 8 oz. active ingredient acephate). Environmentally, orthene seems more desirable than many other insecticides, but the volume and dosage rates make it less economical. In a study when acephate was shown effective at the recommended rate, Dimond (1975) advised tests at reduced dosages and gallonages. Operational difficulties and unexplained factors failed to show differences in the 1977 evaluation, and consequently a more thorough evaluation was requested by the Maine Bureau Forestry. A pilot control project was designed to compare several reduced volume and dosage rates in combination that had shown promise in previously reported studies.