Control of Pyrethroid Resistant Colorado Potato Beetle, Grand Forks, North Dakota, 1991

This experiment was located on the Red River Valley Potato Growers Research farm in Grand Forks, ND. The field was planted on 28 May using cut A-size 'Norchip' certified seed. Plots were four rows, 0.9 m wide, 7.6 m in length, with a 1.5 m fallow aisle at the end of each plot. Plots were arranged in a randomized complete block design with 4 replicates. Soils at this site were Bearden silt-loam and moisture was adequate at planting. Soil systemics were applied just as the potato plants were emerging (21 Jun). Foliars were applied in 2 1 of total material per 0.0088 ha on 27 Jun, 5, 10, 19, and 25 Jul. Asana XL .66 E was combined i with the first treatment of each biological (i.e., Trident II, MYX-1806). Karate 1 E was combined with Trident II and MYX-1806 each time the biological was used. In this case a reduced dosage of each was applied. Monitor 4 E was applied, as needed, following the appropriate predetermined number of biological treatments. Percent defoliation was estimated on 19 Jul.