Cooley Spruce Gall Aphid Control in Christmas Tree Plantings With Aldicarb, Windsor, Connecticut, 1977-79

Abstract

Abstract Cooley aphids on Douglas-fir reduce growth rates and quality for Christmas trees. Aphid galls on Colorado spruce also reduce tree quality. Granular aldicarb (Temik 10G) was first applied on Sept 8'76 at the rate of 10 grams of granules per tree in single bar holes 4 to 6 in deep at the drip line of trees in a plantation established 4 seasons. The hight of the trees averaged about 2.5 ft in Sept '76 and 5 ft in Apr'79. The holes were closed with a kick of the heel. The trees were planted in two row plots spaced 6 ft apart with 5 trees per row spaced 3 ft apart. Temik 10G was applied on one row of each plot. Plots were replicated three times with Colorado spruce and 12 times with Douglas-fir. The soil type was a sandy loam. In May'77 aphid infestations were rated on all trees. Temik 10G was reapplied on Apr 13'78 using 10 grams per tree, and on Apr 10'79 using 20 grams per tree. Ratings of aphid damage on Douglas-fir were made in Aug'78 and Aug'79 on a scale of 0 to 4, with 0 as no injury and 4 as severe injury. Counts of gall infested Colorado spruce also were made.