The Ohio State University shares these four guiding principles of marestail management to help no-tillers battle this problem weed.
Takeaways
- Combination of fall and spring burndown herbicides is most effective. Overwintered plants are difficult to control with spring burndown alone.
- Marestail plants should be dead or dying prior to crop emergence.
- Most populations are resistant to both glyphosate and ALS inhibitors (site 2) such as Classic and FirstRate. Populations in some areas are becoming more difficult to control with 2,4-D also.
- There are no POST options in Roundup Ready or non-GMO soybeans, so in-season control depends solely upon use of effective residual herbicides.
- For control after crop emergence, combinations of several residual herbicides are more effective than single active ingredients.
- LibertyLink and Xtend soybeans provide for effective POST options.
STEP 1. FALL HERBICIDES
- Soybeans—2,4-D plus one of the following: glyphosate, dicamba, Basis, Canopy/Cloak, metribuzin
- Corn—2,4-D plus one of the following: glyphosate, dicamba, Basis, simazine, metribuzin
- Keep herbicide cost less than $10
- Avoid use of other residual herbicides; save them for spring
STEP 2. SPRING BURNDOWNS, FOLLOWING FALL HERBICIDES
- Glyphosate + one of following: 2,4-D, Elevore + 2,4-D, Sharpen, Zidua PRO
- Gramoxone (2 to 3 pt) + 2,4-D + metribuzin
- Glufosinate + metribuzin
- Can add metribuzin (0.3 to 0.5 lb ai) and/or 2,4-D to most of these
- Glyphosate + dicamba (Xtend soybeans)
- Elevore, 2,4-D have plant-back restrictions
SPRING BURNDOWNS, NO FALL HERBICIDES
- Glyphosate + Sharpen/Zidua PRO + 2,4-D + metribuzin
- Gramoxone (4 pt) + 2,4-D + metribuzin
- Glyphosate + dicamba (Xtend soybeans)
- Glyphosate + dicamba + Sharpen (Xtend soybeans)
- Glufosinate + Sharpen + metribuzin
- Metribuzin rates—0.3 to 0.5 pounds per ai
STEP 3. INCLUDE RESIDUAL HERBICIDES WITH SPRING BURNDOWN
- Flumioxazin—Valor and Fierce products, Surveil, Envive/Enlite, Trivence, Panther Pro, others
- Sulfentrazone—Authority products, Sonic, others
- Metribuzin—various products and premixes
- Equivalent of 0.3 to 0.5 lb ai metribuzin
- Add more metribuzin as necessary if rate in premix is low
- Residual herbicide mix should be more complex in Roundup Ready and non-GMO soybeans due to lack of effective POST options (or in Xtend to avoid POST use of dicamba)
- Panther Pro, Trivence
- Metribuzin plus one of following: flumioxazin, sulfentrazone, Sharpen (1.5 to 2 oz)
STEP 4. POSTEMERGENCE OPTIONS
- Roundup Ready or non-GMO soybeans?no effective POST options
- LibertyLink soybeans
- Glufosinate—Liberty, Cheetah, Interline, etc
- Marestail plants less than 6 inches tall
- Xtend soybeans
- XtendiMax, Engenia, FeXapan (plus glyphosate)
- Apply by early June and prior to R1 stage
- Risk of off-target movement; see label and other information from manufacturers and universities
- Enlist soybeans
- Enlist Duo, Enlist One
- Glufosinate
- Most effective: glufosinate + Enlist Duo
Multiple-resistant marestail surviving treatment with (from left to right) glyphosate alone, ALS inhibitor (site 2) alone, and a combination of glyphosate plus ALS inhibitor. Photo from The Ohio State University.
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Options For Burndown Of Marestail In No-Till Soybeans