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Title: COMMON WATERHEMP (AMARANTHUS RUDIS SAUER) MANAGEMENT WITH SOIL-APPLIED HERBICIDES IN SOYBEAN (GLYCINE MAX (L.) MERR.)

Author
item HAGER, AARON - UNIV OF ILLINOIS
item WAX, LOYD
item BOLLERO, GERMAN - UNIV OF ILLINOIS
item SIMMONS, FREDERICK - UNIV OF ILLINOIS

Submitted to: Crop Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/2/2001
Publication Date: N/A
Citation: N/A

Interpretive Summary: Common waterhemp is a very troublesome and widespread weed in soybean production in the midwestern part of the U.S.A. This species can emerge during much of the growing season, and control of this weed with soil- applied herbicides can be variable. We designed and conducted experiments over two years to determine the effect of application timing and herbicide rate of application on the effectiveness of six soil-applied herbicides for common waterhemp control in soybean production. We found that herbicides applied preemergence at planting time provided 18% better control than herbicides applied early preplant 5 weeks before soybean planting. Rate of herbicides overall did not affect control of common waterhemp, but there were some differences between rates with some of the herbicides used. The soil-applied herbicide sulfentrazone controlled common waterhemp and reduced the number of remaining plants better than any of the other herbicides used. All of the herbicides used reduced common waterhemp density and dry weight, compared with the nontreated control. These studies identified differences among herbicides for waterhemp control, and provided evidence of improved control with applications closer to planting. These findings should be useful to other researchers planning research on weed management and to public and private outreach personnel preparing guidelines for control of waterhemp in soybean production.

Technical Abstract: Common waterhemp can exhibit multiple emergence events during a crop growing season. Control of this species in soybean with soil-applied herbicides can be variable. A 2 year field research project was conducted to examine the influence of herbicide application timing and rate on efficacy of six soil-applied herbicides for common waterhemp control in soybean. Four weeks after soybean planting, herbicides applied preemergency provided 18% greater common waterhemp control than when herbicides were applied 5 weeks early preplant. Herbicide rate did not significantly influence common waterhemp control, but differences among the 6 herbicides were evident. Sulfentrazone controlled common waterhemp better and reduced its density more than other herbicides. All herbicides reduced common waterhemp density and dry weight more than the nontreated control.