Potato, Wireworm Control, Pasco, Washington, 1979

Abstract

Abstract The test was conducted in a grower’s solid-set, sprinkler-irrigated field. The soil type was Ritzville silt loam (Calciorthidic Haploxerolls), and the organic matter content was less than 0.5%. The test area consisted of 4 adjacent blocks of 4 different application methods: prep I ant broadcast, at-plant sidedress, seed-piece furrow, and postemergence sidedress. Each plot measured 12.2 m long and 4 rows wide (86.4-cm row spacing). On Apr 20, broadcast applications were made: granules were broadcast with a hand-operated Cyclone grass seeder and liquid formulations with a hand-held, 2-row sprayer with a boom consisting of 4 TeeJet (No. AL80015) nozzles. Liquid formulations were diluted in water to a volume of 0.95 litre and applied at a rate of 224.5 litres/ha at a pressure of 2.1 kg/cm2. The plots were rototilled to a depth of 10.2-15.2 cm within 1 hr after application. On Apr 24-26, potato seed pieces were planted with a 2-row planter and the at-plant sidedress and seed-piece furrow applications were made. On May 30, postemergence sidedress materials were applied 2 rows at a time with tractor-mounted Gandy and liquid applicators in a manner similar to that used with the at-plant sidedress materials. On Sep 24-26, tuber samples were harvested from the 2 center rows of each replicate (from ca. 4.6 m/row). All tubers were washed and examined for wireworm feeding, and the percentages, by weight, of tubers injured and damaged were determined. “Injured” was defined as any penetration of a tuber by a wireworm and “damage” as any injury as severe as described in Sec. 51.1560 and 51.1564 of the U.S. Standards for Grades of Potatoes. All percentages were transformed to arcsine percentage and analyzed by analysis of variance (a modified split plot design in which replications were within application blocks) and Duncan’s multiple range test. Materials that were not applied with all 4 application methods were not included in the analysis.