By Dwight Lingenfelter
With all this wet weather and delay in planting and herbicide application in some parts of the state, you might consider flexibility if you are playing the waiting game. A limited number of corn and soybean herbicides allow you to switch crops if necessary. Here is a list of herbicides that can be used as a burndown or PRE in both corn and soybean.
- 2,4-D LVE — When applied at 1 pt/acre, there is a 7-day waiting period for soybean. This is also the safest use in corn.
- Elevore — Either corn or soybean can be planted 14 days after application when applied at 1 fl oz/acre. Provides control of glyphosate-resistant marestail.
- Glyphosate — This can be used in the burndown and POST in Roundup Ready crops. Increase the rate to 1.5 lb ae/acre for larger weeds.
- Gramoxone SL — Can increase the rate up to 4 pt/acre for larger weeds.
- Harmony — Can be added to the glyphosate burndown at 0.45 to 0.90 oz/acre for both corn and soybeans. Must wait 7 days to plant soybean and 14 days for corn.
- Liberty 280 — labeled up to 43 fl oz/acre in the burndown application. Liberty is most effective on small actively growing weeds under warm temperatures. Use sufficient carrier volume (minimum 15 GPA) and spray tips to get thorough coverage of the weeds.
- Dual (metolachlor) products — Can be used in both corn and soybean for residual grass, yellow nutsedge, and some small seeded broadleaf control.
- Outlook — Can be used in both corn and soybean for residual grass and certain small seeded broadleaf control.
- Warrant — Can be used in both corn and soybean for residual grass, yellow nutsedge, and some small seeded broadleaf control.
- Lorox— Can be used in both corn and soybean. It primarily provides control of annual broadleaves but can suppress certain annual grasses.
- Metribuzin — This product was labeled preemergence at up to 5.3 oz per acre on medium textured soils with greater than 2% organic matter as part of the burndown program.
- Python — Python is effective on a number of annual broadleaf weeds and can be used in both corn and soybean. The use rate range is 0.8 to 1.14 oz/acre (up to 1.33 oz in soybean).
- Sharpen — Labeled for both corn and soybean. Use only the 1 oz/acre in soybean for burndown and add MSO as the adjuvant if planting within 14 days of application. Cannot be used in combination with Valor (flumioxazin) or Authority (sulfentrazone)-containing herbicides.
- Valor — Can be used in both corn and soybean. Corn may be planted 7 days after application at the 2 oz/acre rate (requires minimum of 25% surface residue and 0.25 inch of rainfall between application and planting). Do not tank-mix with common grass herbicides (Dual, Outlook, etc.) in soybean due to injury concerns.
Grass and broadleaf residual products
- Verdict — This is a mixture of the active ingredients found in Sharpen and Outlook. The most common application rate is 13 fl oz/acre for corn and 5 fl oz/acre for soybean.
- Zidua and Anthem Maxx – can be used in the burndown mix and either corn or soybean can be planted and will provide control of many annual weeds.
- Fierce – can be used in both soybean and no-till or minimum till corn to control many annual grasses and broadleaves. In corn, you must wait at least 7 days to plant after application.
- Combinations that include a grass products (Dual, Outlook and Warrant) plus Python would also provide residual grass and broadleaf control for both corn and soybean.