Issues in Weed Management, 2004 Fabián Menalled Cropland Weed Specialist 719 Leon Johnson Hall Montana State University

Weed Science at MSU Herbicide Resistance Herbicide Update Issues in Weed Management, 2004

Cropland Weed Management Web Site Google: Cropland + weed + Montana

Weed Management Handbook Available: December 2004 On-line Extension Publications Montana State University P.O. Box Bozeman, MT

Weed Science at MSU  Herbicide Resistance Herbicide Update Issues in Weed Management, 2004

Herbicide Resistance Innate ability of a species to survive and reproduce after treatment with a dose of herbicide that would normally be lethal

WeedSituationHerbicide Mode of Action Kochiarailways Photosystem II inhibitors (atrazine) wheat ALS inhibitors (chlorsulfuron, metsulfuron-methyl) wheat Synthetic Auxins (dicamba, fluroxypyr) Wild oatbarley Thiocarbamates and others (difenzoquat, triallate) barley Pyrazoliums (difenzoquat, triallate) sugarbeet, wheat ACCase inhibitors (diclofop-methyl, fenoxaprop-p-ethyl, tralkoxydim) cereals ALS inhibitors (imazamethabenz-methyl) Russian Thistlewheat ALS inhibitors (chlorsulfuron) Persian Darnellwheat ACCase inhibitors (diclofop-methyl)

Herbicide Resistance Idaho –Prickly lettuce –Kochia –Russian thistle –Wild Oat –Italian ryegrass –Mayweed chamomile Wyoming –Kochia –Italian ryegrass North Dakota –Kochia –Green foxtail –Wild oat –Redroot pigweed –Wild mustard –E. black nightshade Utah –Kochia

Herbicide Resistance Selection intensity –Herbicide efficacy –Number of herbicide applications / year Weed biology –Genetic variability –Reproduction mechanism Genetics of resistance –ALS or ACCase vs. EPSP synthase

Resistance Management ROTATE!!!!! –Management practices –Crops SITE OF ACTION –Herbicides with different SITE OF ACTION

Herbicide Mode of Action Sequence of events from absorption of the herbicide into the plant until the plant dies

Contact Absorption Toxicity Movement Herbicide Mode of Action

Commercial Products ( Roundup, Ultramax, etc. ) Mode of Action (Amino Acid Biosyntehsis Inhibitors) Site of Action ( EPSPS inhibitor ) Chemical Family ( Glyicines ) Active Ingredient ( Glyphosate )

Herbicide Mode of Action HMOAExample Growth regulators2-4,D; Banvel; Starane Amino acid synthesis inhibitors ALS inhibitors: Glean; Harmony Extra; Everest EPSP inhibitors: Roundup Lipid inhibitorsACC-ase inhibitors: Select; Puma; Hoelon Seedling growth inhibitorsFar-go Photosynthesis inhibitorsTriazines: Bladex Nitriles: Buctril Cell membrane disruptorsDiquat; Gramoxone Pigment inhibitorsCommand

Weed Management in Montana Based on few HMOA –Amino acids biosynthesis inhibitors (Roundup and the Sulfonylureas) –Growth regulators (2,4-D, MCPA) –ACCase inhibitors (Holeon and Achieve )

Weed Science at MSU Herbicide Resistance  Herbicide Update Issues in Weed Management, 2004

Herbicide Update Familiar Faces, New Names

WideMatch, Dow AgroSciences Osprey, Bayer Silverado, Bayer Olympus, Bayer Durango & Glyphomax XRT, Dow AgroSciences Velpar Alfamax, DuPont

WideMatch Clopyralid/MCPA ester + fluroxypyr WideMatch Clopyralid/MCPA ester + fluroxypyr Curtail + Starane Growth regulators Wheat, durum, oat, barley Broadleaf control: Canada thistle, wild buckwheat, ALS-resistant and large kochia. Tank-mixed: Achieve, Discover, Everest, Puma Three-leaf stage to flag leaf emergence Rate: 1.0 to 1.3 pt / A Rotation: 18 months for pea, lentil, and potato Cost: approximately $7.50 to $8.00/A

ALS-inhibiting herbicide Winter wheat Wild oats, Persian Darnel, ryegrass and certain broadleaf weeds Control ACC-ase resistant grasses (wild oat) Emergence to jointing stage Rate: 4.45 oz / A + adjuvant Flathead and Lake Co. Restrictions! Tank-mixed: Curtail, Harmony, Bronate Advance, etc. Rotation: 7 days for wheat; 90 days for lentils, peas and dry beans; 12 months for corn Osprey Mesosulfuron-methyl

Silverado Mesosulfuron-methyl ALS-inhibiting herbicide winter and spring wheat, including durum Wild oat control in Eastern Montana ACC-ase-resistant wild oats Emergence to jointing stage ounces / A + adjuvant Tank-mixed: MCPA ester, Harmony Extra, Curtail, etc Rotation: 7 days for wheat and barley; 90 days for lentils, peas and dry beans; 12 months for corn Cost: $8.75/A + the adjuvant

ALS-inhibiting herbicide spring, durum and winter wheat Cheat grass, downy brome, Japanese brome. Suppression of jointed goatgrass Control ACC-ase resistant grasses (wild oat) Emergence to jointing 0.6 to 0.9 oz./acre in a single application Tank-mixed: Amber, MCPA, Starane, 2,4-D, etc. Rotation: 4 months for Proso Millet, 22 months for corn Cost: Approximately $ 9.00 / Acre Olympus Propoxycarbazone-sodium

EPSP inhibitors Glyphosate stewardship guidelines Durango & Glyphomax XRT Glyphosate

Velpar – Alfamax Velpar – Alfamax Diuron and Velpar (hexazinone) Established alfalfa Contact and residual control One single application during winter Rates = 3.3 – 10 Acres / Unit Pack (14.2 pounds), Mustards, pigweed, chickweed, common lambsquarters Branyardgrass, cheatgrass Dry bulk fertilizer may be coated with Velpar - Alfamax Caution: can damage trees and shrubs

Section 24(c). Special Local Needs Velpar LAlfalfa, dormant forage General weed control Roundup (Original and Ultra Max RT) Peas (Dry), Lentils, Chickpeas General weed control BasagranSeed AlfalfaCanada thistle, mayweed & other weeds ProwlSeed AlfalfaGeneral weed control Sonalan HFPSeed AlfalfaNightshade and Dodder Fusilade DXSeed AlfalfaQuackgrass SencorSeed GrassesBromus Species

ALWAYS READ THE LABEL!!!!!!!!