(E49) POTATO: Solanum tuberosum L., 'Red La Soda' CONTROL OF APHIDS ON POTATOES USING SOIL APPLIED INSECTICIDES AND TREATED POTATO SEEDS, 2002 Jeffrey A. Davis Department of Entomology University of Minnesota 1980 Folwell Avenue, Room 219 St Paul, MN 55108 Tel: (612) 624-2751 Fax: (612) 625-5299 firstname.lastname@example.org Edward B. Radcliffe David W. Ragsdale Green peach aphid (GPA): Myzus persicae (Sulzer) Potato aphid (PA): Macrosiphum euphorbiae (Thomas) Experiments to evaluate the control of Green peach aphid (GPA) and potato aphid (PA) using soil applied insecticides and treated potato seeds at planting were conducted at the University of Minnesota Agricultural Experiment Station at Rosemount, MN. 'Red La Soda' potatoes were planted on 20 and 21 May at a rate of 20 bags/acre or 19,000 plants/acre. Plots were four-rows wide, 50-ft long, with 36-inch between rows and 12 inch between plants. Treatments were arranged in a randomized complete block design with four replications each. Before planting, potato seeds were treated by mixing them with the tested materials and shaking them in heavy-duty plastic bags until the seed pieces were completely covered with the test materials. Band and dribble applications consisted of placing insecticides in-furrow ahead of the seed piece using an electric powered applicator attached to the potato planter. All plots received a weekly application of the fungicide Bravo Zn at a rate of 1-2 pt/acre for late blight control and Guthion at a rate of 1 lb/acre to flare aphids. Aphid counts were made weekly from 18 Jul to 27 Aug. Aphid counts were discontinued after 27 Aug because aphid numbers were dropping due to entomopathogenic fungi. Percent control was calculated as (1- (treatment count/untreated check count)) x 100 for that day. Analysis of variance was performed following transformation of count and percentage data using log (x+1) and arcsin Ö (x), respectively. The level of significance was set at P = 0.05 and the Ryan-Einot-Gabriel-Welsch Multiple Range Test was used to separate means. Results are indicated in Tables 1 and 2. Seed treatments began to lose efficacy 77 days after planting. Usually, this is the time when aphid populations are beginning to rise. Failure of seed treatments at this time can be costly. None of the products kept green peach aphid or potato aphid populations under the economic threshold past 20 Aug.
Arthropod Management Tests – Oxford University Press
Published: Jan 1, 2003