Control of Spruce Gall Midge in Southern ct 1983

Abstract

Abstract Nine insecticides were evaluated for control of spruce gall midge in commercial plantations of white spruce 1 to 2 m tall. Applications were made in either late Apr or early May, or at both times, in a randomized block experiment with 4 replications at Guilford and five at Middlefield. Insecticides at the rate of 1 lb (AI)/100 gal were applied to runoff with a Solo knapsack sprayer. The Apr treatment was applied when white spruce buds were swelling and bud scales were separating, and when adult midges were emerging and beginning to lay eggs; the May application was made when new shoots had elongated 1 to 2 cm. Infestation was rated 0 to 5: 0, no visible infestation; 1, very light visible infestation; 2, light infestation with some swollen shoots; 3, moderate infestation with noticeable swollen and stunted shoots; 4, severe infestation with many swollen, stunted shoots and some dead needles and shoots; 5, very severe infestation with many swollen, stunted and deformed shoots and abundant dead needles and shoots. Infestation on 1982 shoots was rated before treatment and only trees with a rating of at least 1 were treated.