Evaluating Chemical Fallow Herbicides for Potential use in Controlling Glyphosate Resistant Kochia Fabian Menalled & Ed Davis December, 2012
Project Justification During the 2012 growing season there has been several complains on kochia control failure with glyphosate Glyphosate resistant kochia has not yet been confirmed in Montana, but it has been observed in Kansas, South Dakota, North Dakota, Nebraska, and Alberta (Canada) At MSU, we are currently screening kochia seedlings to confirm or reject the presence of glyphosate resistant kochia
Glyphosate Resistance Worldwide: 24 species USA: 14 species Multiple resistance – 2 Mode of Actions: 17 biotypes – 3 Mode of Actions: 5 biotypes – 4 Mode of Actions: 1 biotype Source: Checked Dec. 13, 2012www.weedscience.org
Confirmed glyphosate-resistant weed populations Source: Heap 2012
Why is Kochia Such a Problem? Very competitive Extremely drought tolerate Late maturing Genetically diverse Out-crosses Over 50,000 seeds/plant Tumbleweed Herbicide resistance PNW Weed Management Handbook
Objectives Evaluate soil active herbicides for kochia control in a fallow period in anticipation of glyphosate resistant kochia biotype occurrence in MT Achieve control of kochia seedling through mid-July – Kochia seed germination and seedling establishment after mid-July is unlikely due to dry upper soil profile
Herbicide Selection Criteria Early application (spring burndown) Soil residual activity Treatments: – Gramoxone Super (burndown) & Atrazine, Sencor, Corvus (residual) – Valor, Spartan, and Spartan Charge (burndown & residual) – Glyphosate Percentage control evaluated 45 & 73 days after application Winter wheat: seeded in fall of 2012 to evaluate fallow treatment effects on the crop
Amsterdam, MT Chem fallow, no-till Application: May 1, 2012
Percentage Control LSD = 7.39
Percentage Control LSD = 7.39LSD = 8.35
Approximate Price (Source 2012 North Dakota Weed Control Guide) TreatmentCost $/A (high rate) Roundup7.50 Select7.50 Gramoxone Super11.50 Gramoxone Super + Atrazine15.50 Gramoxone Super + Sencor 75 DF19.50 Gramoxone Super + Atrazine + Sencor 75DF23.50 Gramoxone Super + Corvus42.30 Gramoxone Super + Corvus + Sencor50.30 Select + Valor24.00 Select + Spartan35.65 Select + Spartan Charge + Valor50.96 Select + Spartan + Distinct61.65
Gramoxone (paraquat) Restricted use pesticide Acute toxicity – Fatal if inhaled. May be fatal is swallowed. Harmful in contact with skin. Worldwide: 25 resistant species (43 resistant biotypes) in 13 countries Australia: multiple resistance with glyphosate
Preventing the spread of herbicide resistant kochia Be alert!
Preventing the spread of herbicide resistant kochia Be alert! Prevent weed seed production
Short wheat variety High weed seed production Tall wheat variety Low weed seed production Source: Menalled and Miller
Preventing the spread of herbicide resistant kochia Be alert! Prevent weed seed production Prevent the spread of weed seeds
Weeds are Distributed in Patches
After H. Beckie, Agri-Food Saskatoon Standard weed management conducted at the field level 270% expansion over 6 years Standard weed management + weed shed prevention 24% expansion over 6 years
Preventing the spread of herbicide resistant kochia Be alert! Prevent weed seed production Prevent the spread of weed seeds Develop and Integrated Weed Management program to reduce the selective pressure towards the selection of herbicide resistant biotypes
In Summary Several treatments provided kochia control through mid summer without the use of glyphosate Glyphosate will still be required to control volunteer cereal grain, weedy grasses and other broadleaf weed species as well as susceptible kochia Extra cost Health and environmental issues
Contact us: Fabian Menalled 719 Leon Johnson Hall Montana State University Bozeman, MT