Soil-Applied Herbicides for Soybeans

May 5, 2000
With the majority of Illinois corn acres planted, many growers are turning their attention to planting soybeans. While many have already decided on a weed-management program for this year, there may be some producers still uncertain about how they want to manage their weed spectrum. There are a number of factors a grower needs to consider when making these decisions: (1) Will tillage be a part of the management program, or is no-till production selected for this season? (2) If no-till, was there or will there be an opportunity to apply a burndown to control existing vegetation before planting? (3) What weeds are expected to emerge during the growing season in a particular field? (4) What row width are the soybeans planted in (drilled, 15", or 30"), and will there be the opportunity to cultivate after soybean emergence? (5) What type of herbicide program should be used: a "one-shot" soil-applied program, a planned sequential program (soil-applied followed by postemergence), or a total-postemergence program? Taking all of these questions into consideration will be important in making a wise decision as to the type of weed-control strategy to use for your soybeans this season.

If a soil-applied herbicide is part of your management strategy, there are several new soil-applied herbicide premixes available this season: Domain, Boundary, Extreme, and Backdraft. For more information on these new products, refer to the article New Herbicides for 2000 in issue no. 1 of the Bulletin. Herbicide efficacy ratings for many soil-applied herbicides are presented in Table 1 and Table 2. These tables are reproduced from the Illinois Agricultural Pest Management Handbook 2000. Keep in mind that a number of these soil-applied herbicides also have some foliar activity on certain winter and smaller summer annual weed species and may help control existing vegetation prior to planting soybeans in no-till situations.--Christy Sprague and Aaron Hager

Author: Aaron Hager Christy Sprague