There may be more opportunity to apply a residual burndown program 2 or more weeks ahead of planting with the idea of coming back with a well-timed post-treatment, says Penn State Extension.

The University of Tennessee shares when a residual herbicide is necessary and some options for corn, cotton and soybeans.

A news release from the Weed Science Society of America last week covered the results of a study in Arkansas cotton fields to determine the effect over time of releasing 20,000 glyphosate-resistant Palmer amaranth seeds in a patch, within a 1-square-mile area.

Research over the last couple of years has shown that two shot burndown programs which include either 2 shots in the spring or fall plus spring burndown treatments are needed in areas with a history of poor marestail control due to glyphosate and ALS herbicide resistance.

We have published articles about fall herbicide treatments in C.O.R.N. over most of the last five years or more. Readers can check the archives for those articles, as our suggestions about fall weed control have not really changed much from year to year. Maybe the best thing we can do here instead of regurgitating the same information is to list some of the questions we have received this year about fall treatments, with answers of course.

Effective marestail management programs include appropriate burndown herbicides and also residual herbicides, to control marestail that emerge between soybean planting and early to mid-June.

With the early harvest, this fall offers a great opportunity to tackle fields with perennial weed issues in no-till fields.

Multiple years of OSU research on fall and spring no-till herbicide treatments have consistently shown that the value and effectiveness of residual herbicides for soybeans is maximized when they are applied in the spring, not the fall.