Liquid Options for Corn Rootworm Control, 1991

Experimental plots measuring 2 rows (76 cm row spacing) X 14 m were planted on 7 Jun in a Waukegan silt loam soil at the University of Minnesota Agricultural Research Station, Rosemount. Treatments were arranged in a randomized complete block design with 4 replications. Three different application methods were used: banded ahead of the press wheel; banded behind the press wheel; and broadcast. Treatments were also applied at 1 of 3 different times: at planting; at cultivation; and tank-mixed with the postemergence herbicide bromoxynil (Buctril) 2 E. All pesticides were applied at a rate of 217 liter/ha (20 gal/acre). In order to insure adequate rootworm pressure, approximately 3 m of each plot row were artificially infested with WCR eggs at a rate of 600 eggs per 30.5 cm on 19 Jul using the method of Sutter and Branson (1980). On 21 Aug, 5 roots were dug from each plot, washed, and rated using the Iowa 1-6 scale (subdivided into half-point increments for higher sensitivity).