Registered Insecticides for Control of the Sugarbeet Root Maggot, 1997

Experimental test plots were established 1 mile south and 5 miles east of St. Thomas, Pembina County, ND. Planting was accomplished on 16 May in a sandy loam soil. Fifteen treatments and an rntreated check were replicated four times in an RCB design. Individual plots were four rows (22 inch spacing) wide by 35 ft length. Temik 15 G, Counter CR, Counter 15 G, Lorsban 15 G, and Chlorfos 15 G were applied at different rates. Treatments also varied by insecticide placement: MIF = modified in-furrow, 2-inch band; B = banded over the row in a 5-inch band; IF = insecticide dropped in-furrow with the beet seed. Drag chains followed all treatments for incorporation. Ten beets were removed from the outer two rows on 23 Jul and rated on a 5 point scale (0 = no scars; 1 = 1-4 small scars of pinlead size; 2 = 5-10 small scars to 3 large scars; 3 = more than 3 large scars; 4 = H to 3A of root area blackened by scars; 5 = more than % of root surface slackened, dying beet) to estimate SBRM feeding injury. Plant stand counts were taken just before harvest on the center two rows that were harvested 70 row ft). On 29 Sep the center two rows of each plot were machine lifted, weighed, and sent to the American Crystal Research Laboratory, Grand Forks, ND where they were cleaned, reweighted and adjusted for tare. All data were analyzed using ANOVA and SNK.