Control of the Black Vine Weevil on Concord Grapes in Central Washington1

Abstract

Four granular insecticides were evaluated during 1962 in replicated plots for control of the black vine weevil, Brachyrhinus sulcatus (F.). Aldrin at 3.2, 3.9, 4.9, and 5.6 lb actual per acre, dieldrin at 3 lb, endrin at 2 lb, and Imidan® (phthalimidomethyl- O,O -dimethyl phosphorodithioate) at 2 lb were applied to the soil surface of a vineyard having 5 different cover-crop cultural practices. Applications were made in late May and early June before the adult weevils had emerged. Aldrin at the 4.9- and 5.6-lb rates was most effective. In another experiment where 5 lb actual aldrin granules was compared with a malathion (2.4 lb) plus aldrin (0.25 lb) dust mixture, the aldrin was most effective. In aldrin-treated vineyards mean cluster injuries were less than 1 per cluster and injured berries were less than 1% compared with mean cluster injuries as high as 25 per cluster and up to 54% injured berries in untreated vineyards or those treated with a malathion-aldrin dust mixture. Contact with aldrin granules disrupts the normal behavior pattern of adult weevils so that rather than hiding by day they are found wandering on the soil surface at mid-morning. Adult weevils were killed in the laboratory when subjected to a temperature of 90°F for several hours. Factors responsible for weevil mortality in the vineyard appear to be a combination of toxic effects of aldrin and high soil-surface temperature. Weevils taken early in the morning from a vineyard treated recently with aldrin were kept at room temperature with adequate food for 30 days, indicating that effects of aldrin alone were not lethal.