Sunflower and Rotational Crop (Corn) Response to DPX-R6447 and Sulfentrazone
P. Hendrickson  

The study was conducted on a Heimdal silt loam soil with a 6.7 pH and 2.9% organic matter.  Sunflower (SF290 NL) was seeded on June 11, 1999, into 30-inch rows at 20,000 seeds/A.  DPX-R6447 and sulfentrazone were applied preemergence (PRE) on June 15, 1999 to 20 by 50 ft plots at 1.07, 2.14, and 4.29 oz ai/A and 3, 4.29, and 6 oz ai/A; respectively.  Ethalfluralin applied PRE at 18 oz/A was included as a treated check.   The trial area was reseeded to corn May 29, 2000, into 30-inch rows at 30,600 seeds/A.  Weeds were controlled with post-emergence herbicides and cultivation to reduce the effect of weed interference on corn yield.

Sunflower injury was rated less than 10% in all plots and did not differ significantly from the untreated check (Table).  Sulfentrazone reduced common lambsquarters densities from 73 to fewer than two plants per three ft², and redroot pigweed from 41 to fewer than 10 plants per three ft².  No differences in common purslane and yellow foxtail densities were detected.  Corn injury was rated less than 10% in all plots and did not differ significantly from the untreated check.  Corn yield was not affected by DPX-R6447, sulfentrazone or ethalfluralin carryover.