This time of year, growers are riding in combines and grain carts over thousands of acres, and it’s hard not to find areas of weed pressures that broke or even new green weeds starting to emerge. As you find those areas, it’s important to determine why there was weed pressure in the field and how to properly manage next year.
It was Albert Einstein who said the definition of insanity is doing the same thing over and over and expecting a different outcome. Now is the time to recognize the issues, soon will be the time to learn about the WHY which will eventually lead to the HOW (how do I prevent this or how do I develop a new management system).
To many people weeds are just weeds, but to an agronomist, they are unique vegetations that have many different life cycles and need to be managed accordingly. For example, is your weed pressure issue a winter or spring annual or is it a broadleaf or grass. Knowing this information can help validate the cause of the problem, and this is one of the first steps to eliminate the problem moving forward. Just because fields in the county have major weeds problems, doesn’t mean yours has to as well.
Winter Annual: These weeds will emerge and grow vegetatively in the fall and grow aggressively in the spring followed by reproductive stages.
- Types of weeds
- Marestail, henbit, purple dead nettle, field pennycress
- Types of control
- Mechanical: Tillage – post harvest (if too early, will not provide good control)
- Biological: Drilling or seeding cover crops
- Chemical: Fall burndown or spring burndown
Spring Annual: These weeds will emerge, grow vegetatively and go through reproductive stages all in the spring and summer.
- Types of weeds
- Cocklebur, jimsonweed, lambs quarter, morning glory, ragweed, waterhemp, velvetleaf, foxtail, Panicum
- Types of control
- Mechanical: Cultivating in crop or reducing seed head distribution during harvest
- Biological: Cover crops
- Cultural: Reduce row spacing
- Chemical: Residual herbicide preplant, pre-emergence, post emergence. Contact herbicides using proper rates at the correct weed heights with appropriate spray tips
Harvest Scouting: As you scout during harvest, answering these questions will help you gain better control of weeds in your fields.
1. Where are weeds found?
a. Drowned-out spots
b. Replant areas
c. Across the full field
d. Corn field and/or bean fields
2. What type of weeds
a. Grasses
b. Broadleaves
3. How well is your program rated for these weeds?
a. Good
b. Bad
c. Not labeled
d. Not recommended
4. Is this issue specific to this season?
a. Yes
b. No
5. Is this issue occurring every year?
a. Yes
b. No
About the Author: Todd Steinacher
Steinacher is an ISA CCA Soy Envoy alum and currently supports ISA on agronomic content as well as serving as an Illinois CCA board member. He was recently awarded the 2020 IL CCA of the Year & the 2021 International CCA of the Year. He has over 15 years agronomic experience, currently working with AgriGold and GROWMARK previously. Steinacher has an associate degree from Lincoln Land Community College, a B.S. in agronomy and business from Western Illinois University and a master’s degree in crop science from the University of Illinois at Urbana-Champaign.
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