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Start Clean: Prevent Early-Season Weeds Now

May 2017 

We asked our regional sales agronomists for their top advice on weed control, and their responses were resoundingly similar — “start clean.” With only 34 percent of the U.S. corn crop and 10 percent of soybeans planted this year, there’s still time to bolster your early-season weed control program in order to maximize yields.

  1. Pre-emergence herbicides: If burndown wasn’t an option for you this spring, your fields can still greatly benefit from a pre-emergence application. Pre-emergence herbicides are best used to tackle early-season weeds like kochia, lambsquarter, marestail and giant ragweed. Growers also benefit from pre-emergence herbicides as they reduce the need for post-emergence herbicides and help eliminate early-season weed competition. Pre-emergence herbicides should be applied after you plant the crop and before the plants emerge.

  2. Post-emergence herbicides: If it’s too late for a pre-emergence application, apply a post-emergence herbicide before the weeds reach above four to six inches tall. A well-known fact is that the larger a weed gets, the more difficult it is to control and kill off. And, as that weed grows, it continues to compete with plants for space and nutrients. 

  3. Residuals: Residual herbicides offer growers long-lasting weed control after initial application of the product.

  4. Multiple modes of action: Use multiple modes of action in your program. RSA Bill Kessinger likes to see growers use at least three. This helps ensure weed control and slows the spread of resistant weeds. One mode of action we see more growers turn to is LibertyLink® soybeans. LibertyLink soybeans boast high-yielding genetics and outstanding crop safety through built-in tolerance to fast-acting Liberty® herbicide. Liberty herbicide controls more than 120 broadleaf weeds and grasses, including ALS- and glyphosate-resistant weeds. And to date, there is no documented weed resistance to Liberty worldwide. 

  5. Weather: Unfortunately, Mother Nature does not always stick to the forecast. Weather delays are imminent during planting season, which can often delay your herbicide application timeline. Cold temperatures, heavy rainfall and drought-like conditions can greatly affect the effectiveness of herbicides, allowing “weed escapes,” where weeds end up populating fields when a timely post-emergence herbicide is missed because of weather delays.Think ahead so the weather doesn’t leave you behind.

  6. Scouting: Never stop scouting. Always monitor each field for new signs of weed, insect or disease infestations. This will allow you time to apply that post-emergence herbicide before overpopulation and competition for nutrients become an issue.