Irish Potato, Control of Potato Infesting Aphids, 1994

Abstract

Abstract The experiment was a randomized complete block design replicated six times and was conducted at Presque Isle, ME on land that was in clover in 1993. It was planted 23 May. The 3.0 m space between blocks and the 1.8 m space between the four-row plots were sown to oats on 20 Jun. All rows were planted with an assisted-feed planter 0.9 m apart and 15.0 m long and the healthy whole Katahdin seed (ca. 75 g) were 30 cm apart. Fertilizer and hilling practices were normal for the area. Early and late blight were controlled by eight foliar applications of chlorothalonil. Furrow granular applications of insecticides were made by hand with a plastic tube applying previously weighed amounts of insecticide. Foliar insecticide applications were made with a Century boom sprayer, three nozzles per row at 6.3 kg/cm2 pressure and 0.94 k liter/ha. Numbers of aphids (by species) were counted on a top, middle, and bottom leaf on 25 plants in the middle rows of each plot. When dates of count and application were the same, aphid counts were made prior to applications of the insecticide. Analyses of variance were calculated following transformation of the data using logl0(x + 1). Transformed means of the total number of wingless aphids were compared using Fisher’s LSD Test and then applied to the actual means. The soil was classified as Caribou Loam, pH 5.2. Total monthly rainfall for Jun, Jul, and Aug was respectively 10.9, 9.6, 3.3 cm. The average temperature for each of the same 3 months was 17.9, 20.3 and 17.7°C.