P. ALASKENSIS CONTROL WITH DIMILIN ON WHITE SPRUCE, 1976

Abstract

Abstract On June 7 , branches on field trees of white spruce were sprayed to the drip point with 1 of 6 treatments; tap water (check), 0 . 2 5 , 2 . 5 , 25, 250, and 2500 ppm a . i . Dimilin W-25. There was a mixed population of ten 2nd and 3rd instar yellowheaded spruce larvae on each branch. Dacron mesh bags were placed over the branches to contain the larvae. Three replicate branches, each replicate branch on a different tree, were used for the Dimilin treatments and 6 replicate branches, each on a different tree, were used for checks. Mortality counts were taken 10 days after treatment., On June 8 , a second experiment was conducted using 3-year old potted white spruce trees. Each tree had a mixed population of 3rd and 4th instar larvae and was sprayed to the drip point with the same treatments as above. Again, 3 replicate trees were used for each Dimilin treatment, 6 replicate trees for checks, and a dacron mesh bag was placed over each tree to contain the larvae. Mortality counts were taken 11 days after treatment.