Spring Burndown Applications
Travis Legleiter, Weed Science Professional Assistant, Department of Botany & Plant Pathology, Purdue University
The calendar says its spring, although Mother Nature seems to disagree with a light dusting of snow on the ground on March 21st. Either way, warm weather will eventually arrive and with it winter annual weeds. These weeds will need to be burned-down before planting no-till crops.
Marestail has become a predominate weed in Indiana no-till soybean fields that must be effectively controlled with a spring burndown. Many populations within the state have become resistant to glyphosate and require additional herbicides and/or burndown applications for complete control. Producers need to formulate an effective burndown program that controls existing weeds and include a residual herbicide to suppress further emergence.
Marestail plants that are not controlled prior to soybean emergence will likely persist throughout the season in conventional and Roundup Ready soybean fields, as post-emergence options are limited and often none. Also plants, such as the two pictured that are injured by an ineffective burndown will essentially be hardened-off and become even tougher to control. These plants, although injured will continue to grow and produce seed to contribute to another generation to compete with your crops.
For more complete details of controlling marestail, please refer to our recently updated Control of Marestail in No-till Soybeans.
Click image to enlarge
Pic 1. A marestail plant injured but not controlled by an ineffective spring burndown. This plant will become harder to control and likely persist through out the growing season and produce seed.
Pic 2. A marestail plant with multiple axillary shoots as a result of a marginal burndown that only controlled the terminatl growing point.