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Downy brome and Medusahead Control in Rangelands (1) with Rimsulfuron. Ronnie G. Turner*, Jerry R. Pitts, Mike T. Edwards, Norman D. McKinley, C. William Kral, Craig M. Alford, John D. Cantlon DuPont Crop Protection 8295 Tournament Drive, Suite 300 Memphis, TN 38125
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Downy brome and MedusaheadControl in Rangelands (1) with Rimsulfuron Ronnie G. Turner*, Jerry R. Pitts, Mike T. Edwards, Norman D. McKinley, C. William Kral, Craig M. Alford, John D. Cantlon DuPont Crop Protection 8295 Tournament Drive, Suite 300 Memphis, TN 38125 (1) Rimsulfuron is not currently registered in Rangelands
Downy BromeBromus tectorumPhotos: Steve Dewey, Utah State University; Chris Evans, University of Georgia
Downy Bromeaka: cheatgrass • Invasive grass - Native of southern Europe • Now Infests ~ 100 Million Acres in US • Quick Invader of heavily grazed rangeland, burned areas, and other disturbed sites • Winter Annual • Dev large root system fall to spring; robs moisture • Deters native grass seedlings; reduces population • Dries down quickly by early summer; extended wildfire hazard • Early/often wildfires prevent native grass/sage regeneration which can decrease wildlife habitat • Little Grazing Value • Bad taste; pulls up easily • Sharp seed pods injure mouths of grazing animals
MEDUSAHEADTaeniatherum caput-medusaePhotos: Steve Dewey, Utah State University – Bugwood web site
MEDUSAHEAD • Invasive grass – Native of Eurasia • Infests large areas of PNW, CA • Usually more prevalent on Clay soils, but has also been found on sandy soils • Winter Annual • Repro by seed; matures 2-4 wks later vs. other annual grasses • Fibrous root system – develops faster than downy brome • Depletes upper soil moisture early season (reduces germination potential for native grass seed) • Dead stems decompose slowly forming dense mats; increased fire potential • Little Grazing Value • High silica content (unpalatable); stiff awns, hard florets can injure eyes, mouth of cattle
Rimsulfuron • DuPont Sufonylurea Herbicide • Inhibits acetolactate synthase (ALS) • Registered for Use in Field Corn, Potatoes, Tomatoes; registration pending in Fruit, Nut, Vine crops, and future uses expected in Roadsides and Rangelands • Pre and Post activity on Grasses and Broadleaf Weeds • Root and Foliar uptake; moves in xylem and phloem • Behavior in Water and Soil • At 25°C, half-life in water at 4.6 (pH 5) to 0.3 (pH 9) days • Across 4 soil types, half-life ranged 1.7 to 4.3 days at 86°F (30°C) • In Aqueous Solutions, half-life at 68°F (20°C) and pH 7 = 24 days at 50°F(10°C), pH 7 half-life at 144 days
Rimsulfuron – Downy BromeApplication Timing: late Oct – early Dec
Rimsulfuron + Telar®Application Timing: late Oct – early Dec
Rimsulfuron – MedusaheadApplication Timing: late Oct – early Dec No. Tests ( )
Rimsulfuron + Telar®Application Timing: late Oct – early Dec
Downy BromeRangeland Trial • Location: Pleasanton, NE • Application Date: 20-Nov-2005 • Application Equipment: CO2 Sprayer • Application Volume: 14 gal/ac • Weed Stage: Downy Brome, 2 to 4 tillers • Crop Stage: Western Wheatgrass 2 to 4” • Evaluation: 230 DAT (days after treatment)
MedusaheadRangeland Trial • Location: Boise, ID • Application Date: 13-Oct-2005 • Application Equipment: CO2 Sprayer • Application Volume: 20 gal/acre • Plot Size: 10’ X 30’ X 3 Reps • Pest Stage at Application: • Senescent Medusahead; Early Germination
Rimsulfuron – SummaryIn these trials, • Rimsulfuron provided excellent control of Downy brome • Rimsulfuron provided good control of Medusahead rye (fewer tests) • Install further tests in Fall 2006 especially for Medusahead • Install Plant Back trials to evaluate Native Grass tolerance following Rim applications • Field Trails and University Field Station - NCal
THANK YOU!! • QUESTIONS ???
Cheatgrass / MedusaheadReferences (web sites) • Cheatgrass • http://extension.usu.edu/rangeplants/Grasses/cheatgrass.htm • www.pnl.gov/pals/resource_cards/cheatgrass.stm • www.usgs.gov/invasive_species/plw/prescribedfire.html • A homeowners guide to cheatgrass. Jay davison, Ed Smith, Cooperative Extension, University of Nevada, Reno • www.explorebiodiversity.com/problem_plants/species/Cheatgrass.htm • www.wy.blm.gov/cheatgrass/index.htm
Cheatgrass / MedusaheadReferences (web sites) • Medusahead • www.cdfa.ca.gov/phpps/ipc/weedinfo/taeniatherum-caput-medusae.htm • http://californiarangeland.ucdavis.edu/water_quality/MEDUSA.HTM • www.yolorcd.org/weeds/medusahead.shtml • www.oregon.gov/ODA/PLANT/WEEDS/profile_medusaheadrye.shtml • www.cdfa.ca.gov/wma