Potato, Wireworm Control with Dyfonate and Phorate, College Place, Washington, 1982

Abstract

Abstract A test was conducted in a solid-set, sprinkler irrigated field at the College Dairy, Walla Walla College. The soil type was Yakima silt loam (Cumulic Haploxerolls), organic content unknown. On 27 April 1981, 20 soil samples were taken at the test site with a posthole digger to a depth of 18 inches; 18 sugarbeet wireworms were found for an estimated density of 3.6 wireworms/ft2 . Treatment plots were arranged in a randomized complete block design, replicated four times, and the plots measured 25 ft long and 11.3 ft wide (four rows; 34-inch row). Dyfonate granules were broadcast with a hand-operated Cyclone grass seeder on 3 Nov. 1981 for the fall application and on 6 Apr. 1982 for the spring application. The treated plots were rototilled immediately after application. On 6 May 1982, potatoes were planted with a two-row planter. Seed piece furrow applications were made with Gandy applicators mounted on the planter by applying the granules in a 1-inch band in the planter shoe, level with and directly ahead of the seed pieces. On 14 June 1982, the postemergence topical application of phorate was made by dribbling the granules over the row. All plots were then similarly treated with Temik (3 lb(AI)/A) and hilled with a rotary cultivator. On 4 October 1982, tuber samples were harvested from the two center rows of each plot (ca. 12 ft/row). All tubers were washed and evaluated for wireworm feeding damage, based on percentages by weight. Damage was defined as any injury as severe as described in Sec. 51.1560 and 51.1564 of the U.S. Standards for Grades of Potatoes. Percentages were transformed to x+0.5 before analyzing by analysis of variance and Duncan’s multiple range test.