When making production plans for this upcoming growing season, weed management should be at the forefront of your thoughts. In order to “start clean and stay clean” here are some important things to think about. What are your main weed problems? What are the life cycles of the problem weeds? What is the availability of equipment to ensure proper herbicide timing? What were the past herbicide programs and are there issues with herbicide resistance? What herbicide plan will you make for this season?
First thing to think about is what your weed problems are. In my area the three major players would be marestail, waterhemp and giant ragweed. Across most of the entire state you probably deal with at least one if not all three of these. Proper identification is critical when putting a plan together. No herbicide is a silver bullet by itself and different species of weeds require different modes/sites of action.
The life cycles of the weeds are an important factor as well. Winter annual weeds may require a more aggressive spring burndown or the use of a fall burndown with a residual in order to provide the best start. Spring/summer annuals, which include some more troublesome weeds such as lambsquarter and waterhemp, require early action and the use of layered residuals in order to keep them from becoming problems.
A second factor to consider will be the availability of equipment to ensure proper timing of herbicide applications. Timing of application has become critical in proper weed control to ensure the effectiveness of the products we use. Whether this means getting your post pass scheduled with your local co-op or custom applicator or getting your own spray rig ready for post spraying season, it is an important step.
Additionally, early canopy closure helps soybeans outcompete late emerging weeds for sunlight, which will help ensure clean fields throughout the season. Early canopy closure has also been shown to not only be great for weed control but also for high yields within soybean production.
The last major factor to consider is past herbicide programs and any herbicide resistance issues that might have been noted in previous seasons. A herbicide program should not be used continuously on the same fields year after year without some sort of rotation, whether to a different crop or a different herbicide program. This step is important to help ensure the effectiveness of a program for years to come instead of accelerating chemical resistance within a field or population of weeds.
Once these three factors have been looked at it’s time to put your final plan together. I like to incorporate at least 4 modes of action with at least 2 different types of residuals stacked within the plan. A potential plan could incorporate 2 different residuals, such as Outlook®, metribuzin, or Dual®. I like the use of dicamba preemerge as a burndown only, then following up with a fomesafen product myself. A lot of these ideas can be achieved by using today’s prepackaged tank mix products such as Boundary® or Prefix® among many others from all different types of respected companies.
Paying attention to these basic factors will greatly help you achieve a more effective and efficient weed control plan. I wish you all the best of luck going into this growing season. It has been a challenging start but hopefully that will translate into smooth sailing for the rest of the year