Due to the increasing unpredictability of weather patterns and growing weed problems, farmers need to prepare for next season now more than ever. One way to do this is by using a fall residual application program for winter weed management. That was the topic of CropLife Media Group’s recent Webinar, “Let’s Talk: Fall Residual Applications and What Your Customers Need to Know,” sponsored by Valent’s Valor and Valor XLT herbicides.
Speakers included Dr. Kevin Bradley, associate professor/state weed scientist, University of Missouri, and Dr. John Pawlak, product development manager, Valent U.S.A. Corp., who addressed the agronomic benefits and misconceptions about fall applications and offered talking points for retailers’ customers.
Fall Residual Considerations
According to Bradley, there are four main considerations to keep in mind when deciding whether or not to use residual herbicides in the fall:
- Spring weather uncertainty: “We never know what we’re going to get weather-wise in the spring, and that’s one of the main things driving fall herbicide applications,” said Bradley.
- Impact on soil conditions: A University of Missouri research project on the effects of winter annual weeds on soil temperature found that winter weed removal achieved through residual fall herbicide applications increased soil temperatures by as much as five degrees in corn and as much as eight degrees in soybeans. Soil moisture also increased significantly with winter annual weed removal.
- Other pest interactions: According to Bradley’s research, winter weeds are found to be far more likely to host soybean cyst nematode (SCN) and other problematic insects than fields treated with a fall residual application.
- Weed management: Residual herbicide programs are the way to go when dealing with winter annual weeds because they ensure control of virtually all weeds up to spring planting time.
“I personally believe that fall herbicide applications are 95% about preventing winter annual weeds,” said Bradley in conclusion. “There are a lot of people out there that may think they have some magical solution for killing weeds in-crop once the crop has emerged, but I personally do not. Residual fall herbicides are excellent and I recommend them all the time.”
According to Pawlak, use of Valor herbicide in corn and Valor or Valor XLT in soybeans as part of a fall burndown program has many benefits, including easier control of winter annual weeds, lower insect pressure, an earlier spring planting date and decreased loss of both soil moisture and nitrogen fertilizer.
Both of the Valent herbicides feature low use rates (2-3 oz./acre) and a wide window for application timing (Oct.-Feb.), based mostly on geography and seasonal temperatures. There are also financial incentives under the Roundup Ready PLUS rebates (soybean growers can earn up to $7.50/acre).
Valor is also particularly effective on marestail, according to Pawlak. “The best most effective strategy for controlling marestail is to get it before it germinates in the fall,” he said. “Unfortunately, when marestail does actually germinate it is very small and blends into the soil very well, and generally if you have marestail in the field in the fall you won’t even see it. So pre-emergence is the number one option.”
If you missed our recent Webinar, “Let’s Talk: Fall Residual Applications And What Your Customers Need To Know,” you can view the archived version now. Click here to register. Note: We have been approved for one CEU in pest management for Certified Crop Advisers who attend this one-hour session.