Marestail, also known as horseweed, competes with soybeans throughout the growing season, reducing crop yields. In a 2010 Ohio State University study, soybeans yielded 51 bushels per acre when burndown treatment failed to control emerged plants; 57 bushels per acre when the burndown was effective, but there was no residual herbicide; and 65 bushels per acre when the burndown was effective and effective residual herbicides were used.

We have discussed this in the past, but it probably requires a review again with no-till wheat and other seedings commencing:

The warmer, drier conditions of the last couple of weeks have allowed producers to start spring planting operations in many states.

This is a revision of an article we published in C.O.R.N. two years ago, when rain kept us out of fields until early June in some cases.

There have been more reports of unsuccessful burndown of cover crop and volunteer wheat this spring.

Mark Loux of Ohio State Univeristy presents soybean burndown options for control of marestail.

Several years ago a dealer commented to me that he didn’t know why he would ever need to recommend metribuzin to a grower.

The months between this year’s harvest and next spring’s planting are prime time for winter annual weeds to take over fields.

I have had a number of calls about burndowns not being effective for no-till soybeans. Poor control can be attributed to a number of reasons, weeds were too large, gallonage was too low, and wrong products or adjuvants were used. But the question is what to do now.