Potato Insect Control with Alternate Row Treatments of Soil Applied Systemic Insecticide, 1975

Thimet 15G was applied as in-furrow, split-band treatments at 2 lb a.i./acre to ‘Russet Burbank’ potatoes planted May 19 to 21, at Grand Rapids, Minn. The experiment compared the following: all rows treated, alternate rows treated, and untreated potatoes in 0.9 acre plots with 3 repli-cations. The soil type is a sandy loam with low organic matter. Eptam was applied preplant and Lorox at emergence for weed control. Dithane M-45 fungicide was applied at potato emergence and again 10 days later. Duter fungicide was applied 7 times beginning in mid-July. No insecticidal sprays were used. Insects were counted on 50 randomly selected, mid-plant leaves/plot. In the alternate row plots 25 leaves were selected from treated rows and 25 leaves selected from untreated rows. Plots were sampled at 2 week intervals, June 30 to September 5. Counts were made of nymphs of the potato leafhopper and apterae of the green peach aphid and of the potato aphid. The plots were harvested September 26 to 29. Yields were taken from 4,100 ft2 subplots within each main plot.