George P. Markin
Published: 1983
Total Pages: 8
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Carbaryl is registered for control of the western spruce budworm (Choristoneura occidentalis Freeman), at the dosage rate of 1.12 kg per hectare. That rate and two lower ones were field tested in western Montana in July 1979 to determine if a lower rate would be as effective as the registered dosage. Each dosage was applied to five randomly selected 20-ha plots by helicopter with Beecomist nozzles while larvae were in the fifth and early sixth instars. Reduced dosages of 0.28 and 0.56 kg a.i. per hectare resulted in 83 and 93 percent population reduction, respectively, compared with 93 percent population reduction for the registered dosage of 1.12 kg a.i. per hectare.