With a variety of new seed-tolerance traits coming to the market and recent approvals for over-the-top application, it’s no surprise that dicamba is the talk of the (herbicide) town right now.
Benefits of dicamba include:
- Control of weeds that have developed resistance to other modes of action (such as glyphosate)
- The potential for up to 14 days soil activity for small-seeded broadleaf weeds (dependent upon precipitation)
- Extended application flexibility to before, at and after planting.
But dicamba also presents some new challenges to farmers looking for different options for weed control.
“Dicamba has some label restrictions I’ve never seen before,” says Aaron Hager, Ph.D., associate professor of weed science at the University of Illinois. “So you need to really look at the label carefully and don’t assume anything.”
For example, some label restrictions on dicamba products include both minimum and maximum wind speeds, and if rain is expected within 24 hours you cannot apply. The label also requires buffers that may be confusing.
“If farmers are spraying downwind, there must be a 110-foot-buffer where you cannot apply dicamba,” says Hager. “You do not know where that buffer will be until you pull into that field. It all depends on wind direction.”
Additionally, there is a maximum boom height, meaning the boom cannot be more than 24-inches above the canopy.
The Bottom Line
Dicamba is another tool farmers can use for weed control, but it must be used with care.
While following label instructions has always been important, ensuring that all herbicide options remain as effective as possible makes attention to the details and label instructions even more critical today.
- Only use approved dicamba formulations on tolerant soybean varieties. Recently-approved formulations include DuPont’s FeXapanTM with VaporGripTM technology, BASF’s EngeniaTM and Monsanto’s XtendiMaxTM with VaporGripTM
- Read and follow the label instructions. Adhere to wind speed, buffer restrictions, boom height, weather conditions and application rates.
- Only use approved nozzles.
- Thoroughly clean equipment. Avoid all contact of dicamba with all non-Roundup Ready® 2 Xtend crops.
- Use dicamba as part of a diversified weed management plan with multiple effective modes of action. Tank-mix partners have recently been approved for Engenia, FeXapan and XtendiMax and can be found at the preceding links.
- Use any other dicamba formulation other than EngeniaTM, FeXapanTM or XtendiMaxTM on Roundup Ready® 2 Xtend crops.
- Tank-mix with unapproved partners.
- Ignore the pesticide label. If you have questions, consult your local crop advisor.