(E82) POTATO: Solanum tuberosum L. 'Russet Burbank' Colorado potato beetle (CPB); Leptinotarsa decemlineata (Say) Robert A. Suranyi Craig A. Longtine David W. Ragsdale Edward B. Radcliffe Josef Munyaneza Department of Entomology University of Minnesota 219 Hodson Hall Saint Paul, MN 55108 Phone: (612) 624-8718 Fax: (612) 625-5299 Email:
[email protected] CONTROL OF COLORADO POTATO BEETLE, 1998B: Potatoes were planted on 21 May at the University of Minnesota Northwest Experiment Station, Crookston, Minnesota. Treatments were replicated four times in a CR design. Plots were 4 rows wide (36-inch row spacing) by 50 ft long with 12-ft alleyways separating plots. Admire was applied in-furrow using a CO 2 pressurized sprayer delivering 60 gpa at 35 psi prior to closing the seed bed. Foliar treatments were applied with a tractor mounted sprayer delivering 55 gpa at 65 psi with a single nozzle per row. All foliar applications were made on 4 Jul. On 2 Jul, pre-treatment counts of small larvae (1-2 instars) and large larvae (3-4 instars) were made on 4 plants per plot. On 7 Jul, post-treatment counts of larvae were made from whole plant inspections of 5 randomly selected plants per row in each of the middle two rows. Percent defoliation for each plot was estimated from whole plant inspections of 5 randomly selected plants per row in each of the middle two rows on 15 Jul. Percent control of CPB was calculated as (1-(post-treatment count/pre-treatment count)) x 100 and analyses of variance was conducted after transformation of count and percentage data using log 10 (x + 1) and arcsin (check)(x), respectively. Admire provided 100% control of both small and large CPB larvae. Agenda, Provado, Spintor, Agrimec, and Thiodan were very successful in controlling both small and large larvae. Asana was also very effective against CPB. However, it controlled more small larvae than large larvae. Imidan provided the lowest control, reducing the population of both small and large larvae to about half. Although Furadan was unsuccessful in controlling large larvae, it was very effective against small larvae.
