By Scout Nelson
Fall weed control is crucial for farmers and land managers to ensure cleaner fields in the spring.
“Certain residual herbicides applied in the fall can provide weed control in the early spring, allowing growers to start with clean fields,” said Greg Dahl, president of the Weed Science Society of America (WSSA). “This can be especially important if the spring becomes wet and sowing is delayed.” says Dahl. “In fact, post-harvest fall weed control might be the ideal time to eliminate your most troublesome weed species,” says Dahl.
“Whenever managing any weeds, consider both your purpose and your timing,” said Aaron Hager, Ph.D., a WSSA member and Weed Science Extension Specialist at the University of Illinois. “Winter annual weeds like marestail or horseweed are easier to control in the fall while they are still small. If left untreated after harvest, most winter annual weeds that successfully overwinter often will be more difficult to control in the spring.”
Hager recommends scouting and mapping weeds after harvest, as winter annuals may not emerge immediately. Hager also advises caution with fall herbicide applications, particularly with summer annual weeds. He points out that many summer annuals have prolonged emergence patterns, making them better suited for spring control.
For perennial weeds, fall herbicide applications can be more effective, as the herbicide can translocate to the roots more efficiently compared to spring applications.
In addition, fall applications may allow for higher herbicide rates without the risk of crop damage, though farmers should carefully plan fall residual herbicide use to avoid limiting crop options for the spring.
“It’s better to start harvest and tillage operations from weed-free to low-weed infestation fields, and lastly, to weedy parts and fields,” said Rodrigo Werle, Ph.D., a WSSA member and University of Wisconsin-Madison Extension Cropping Systems Weed Scientist. “Cleaning your equipment – especially combines – after use in weedy areas is also a best management practice to minimize weed dispersal.”
For more information, WSSA Fact Sheets and local Extension weed scientists are valuable resources.
Photo Credit: gettyimages-zoomtravels
Categories: Kansas, Crops