While unpredictable weather may delay application timing of spring herbicides, more growers are adding a burn down application in the fall to their weed management program.

Though the focus when applying a fall burn down is to control of winter annual weeds, a fall burn down provides numerous benefits for soil health and pest management.

A fall burn down application will provide control of winter annual weeds, including marestail, that usually germinate in the fall. Applying herbicides to these weeds in the fall, at the beginning of their growing season, will provide more efficient control than if a herbicide application is put on hold for the spring – targeting fully-established weeds.

Applying a burn down in the fall helps to provide flexibility in the spring. Often, spring weather can be unpredictable, and there are fewer days for optimal herbicide application in spring than in fall.

“Over the last two years, many growers have faced a compressed spring because of cold and wet weather, resulting in less time to apply a pre-plant or burn down herbicide before planting,” said Mark Oostlander, BASF’s technical market manager

“A burn down application applied in the fall, when there are more suitable days for fieldwork, provides certainty that an application can be completed.”

A recent study conducted by Kevin Bradley of the University of Missouri found that fall burn down applications also result in increased soil temperature. The study found that spring soil temperatures increased by up to five degrees in corn and eight degrees in soybeans when a residual fall herbicide was applied.

Winter annual weeds can also serve as hosts for other pests that might overwinter in crop fields. Pests, including soybean cyst nematode and black cutworm, are easier to control in the fall by eliminating winter weeds.