Control of Aphids on Irish Potato, 1997

The experiments were RCB designs replicated 5 times and were conducted at Presque Isle, ME on land that was in clover in 1996. They were planted 02 Jun. The 3.0-m space between blocks and the 1.8-m space between the four-row plots were sown to oats on 10 Jun. All rows were hand planted 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 7 foliar applications of mancozeb. Furrows applications of insecticides were made by sprinkle can. Foliar insecticide applications were made with a Century boom sprayer, 3 nozzles per row at 5.6 kg/cm2 (80 psi) pressure and 0.47 kl/ha (50 gpa). Numbers of aphids (by species) were counted on a top, a middle, and a bottom leaf on 20 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 log10(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 5.6, 6.6, and 10.3 cm. The average temperature for each of the same 3 months was 17.7, 20.8, and 18.3 deg. C.