Potatoes were planted 18 May, at the Red River Valley Potato Growers Research Farm (RRVPGA), Grand Forks, ND. Plots were of variable length with 38-inch row spacing, randomized in complete blocks with 3 replications. All beetle larvae were counted on every plant in each replication until a minimum of 200 larvae were found. Insecticide treatments were applied using a CO2 powered hand-sprayer delivering 50 gal water/acre at 35 psi. Treatments were applied 7 Jul and evaluated 24 h later on 8 Jul. Subsequent evaluations were not possible because of the aerial application of insecticide to the entire field on 9 Jul.