Colorado Potato Beetle Control, 1994

Abstract

Abstract ‘Snowdon’ variety potatoes were used to test nineteen insecticides for control of Colorado potato beetle (CPB) at the MSU Montcalm Research Farm in Entrican, MI. Potatoes were planted 12 inches apart with a 34 inch row spacing on 4 May. Plots were 40 feet long by three rows wide and arranged in a randomized complete block design with four replications. Plots were separated by at least 5 feet of bare ground. Fosthiazate in-furrow treatments were incorporated into the soil through rototill on 3 May. An Admire treatment was applied in furrow on the potato seed with a CO2 backpack sprayer (8005 flat fan single nozzle, 30 psi) on 4 May. Foliar treatment applications were applied on 16, 23 Jun, 1 and 7 Jul using a tractor-mounted sprayer (30 gal/acre, 40 psi). Preplant Fosthiazate treated plots also received foliar treatments of Asana and piperonyl butoxide (PBO). Rain occurred on 24 Jun and 7 Jul within hours after spraying. Insecticide effectiveness was determined through postspray counts for all stages of CPB (small larvae = 1 st and 2nd instar, large larvae = 3rd and 4th instar) by searching two randomly selected plants from the middle row of each plot on 21, 28 Jun, 5 and 12 Jul. Plots were assessed for percent defoliation on 28 Jun, 5, 8 and 12 Jul. Plots were sprayed 13 Jul with Imidan and PBO (except for two of the Agrimek plots) to control summer adults emerging from poor treatments and migrating toward other research plots. All plots were sprayed for the same reason with Agrimek on 23 Jul and 11 Aug. Potatoes in the middle row of each plot were harvested on 2 Sept. Potatoes were separated by size.