Control of douglas-fir tussock moth by aerially applied Dimilin (TH 6040)

Abstract

Epidemic Douglas-fir tussock moth larval populations treated with 2.0 oz, 1.0 oz, and 0.5 oz per acre of aerially applied Dimilin were reduced 99.7 percent, 92.2 percent, and 89.7 percent, respectively, at 35 days postspray. Numbers of surviving larvae per 1000 in² were significantly different (a) at 35 days postspray, between the 2.0-oz treatment and the 1.0-oz and 0.5-oz treatments; and (b) at 28 and 35 days postspray, between the three Dimilin treatments and untreated checks. Analysis of percent unadjusted mortalities showed significant differences between the 2.0-oz treatment and the 1.0-oz and 0.5-oz treatments at 14, 21, 28, and 35 days postspray. Sample trees were heavily defoliated only in untreated and 0.5-oz treated plots.

Citation

Hard, John S.; Ward, James D.; Ilnytzky, Steven. 1978. Control of douglas-fir tussock moth by aerially applied Dimilin (TH 6040). Res. Pap. PSW-RP-130. Berkeley, CA. U.S. Department of Agriculture, Forest Service, Pacific Southwest Forest and Range Experiment Station. 6 p