2010 Georgia Grazing School:

Transcription

1 21 Georgia Grazing School: Newer Weed Management Tools in Grazed Pastures Tim Murphy University of Georgia 21 Grazing School for Milk Producers 1 Moultrie, GA 2 Common Bermudagrass, Ragweed and Nitrogen Fertility Examples for the Southeast Broomsedge Lbs/bermuda/ac General indicator of low ph (<5.4), low P and low K Affected by grazing Sericia lespedeza Extremely tolerant of low ph, P and K Bahiagrass and Common bermudagrass N = 34 lbs/ac More tolerant of low K than hybrid bermudagrass Also more tolerant of close grazing 3 What is the Economic Threshold? Do I spray or fertilize first? Rule of thumb: When weeds are more than 2% of the pasture. Woolly croton 4 Spray first. Control existing weeds. Begin soil-test based lime and fertilizer program

2 21 Georgia Grazing School: What do animals prefer? Grazing for Weed Control Small weeds are more palatable Many weeds have comparable protein levels to forages Good fencing and cattle numbers are needed S. Forages 3rd Ed. Broomsedge is intolerant of early, heavy continuous grazing Examples of plants intolerant of heavy, continuous grazing Kudzu Johnsongrass Little barley (highly dependent upon timing) Dogfennel (sheep) Briars (goats) 9 1 Moulton, AL Digestibility of select cool season weeds Do we really want to eliminate all weeds from pastures? 11 Hoveland et al.,

3 21 Georgia Grazing School: Weeds in grazing situations serve multiple purposes Digestibility of select warm season weeds Can dilute toxins in tall fescue during critical times Chickweed, crabgrass, dallisgrass, lespedeza Can extend grazing season and improve productivity Crabgrass in tall fescue Can improve quality Crabgrass and Johnsongrass Chickweed, curly dock, shepherds 14 purse and tall fescue mixture. Eatonton GA Hoveland et al., 1986 Mowing Too late to prevent competition. No selectivity. Perennials will regrow. May prevent weed seed production. Consistency is key to effective weed control with mowing. About $12 to $14/acre About $1/acre including 1 qt/a 2,4-D More than $12/acre Mowing Mowing 3 times per year for 2 years provided 8 to 9% control of ironweed and goldenrod

4 21 Georgia Grazing School: Herbicides and Legumes Establish legumes after good weed control has been practiced for 1 to 2 years. 2,4-D amine is safe on white clover and lespedeza. Late summer mowing of dogfennel provided 8% control 19 2 Haying and Grazing Restrictions for Dairy Animals (Cattle and Goats) Lactating Herbicide Haying and Grazing Restrictions for Various Livestock Species Non-lactating Grazing Hay Grazing Hay Metsulfuron Cimarron Plus Milestone Forefront Chaparral (14d) (14 d) Grazon P+D 3 3 Remedy 14 NS* Weedmaster 3 3 2,4-D Beef Horses Goats Herbicide 21 *Next season. Beef Grazing Horses Goats Hay Metsulfuron Cimarron Plus Milestone Forefront Chaparral (14) (14) (14) Grazon P+D Remedy Weedmaster ,4-D 22 Bitter sneezeweed When do you spray? Winter annuals - henbit, chickweed, buttercups, thistles November through March Summer annuals - spiny amaranth, bitter sneezeweed April through mid-july Perennials growth stage dependent Spray this size 23 Not this size 24 4

5 21 Georgia Grazing School: Herbicide Options 1. 2,4-D 2. dicamba (Vanquish, Banvel) 3. 2,4-D + dicamba (WeedMaster, others) 4. dicamba+ diflufenzopyr (Overdrive) 5. diuron (Direx, Diuron) 6. triclopyr (Remedy). imazapic (Impose,Panoramic) 8. 2,4-D + triclopyr (CrossBow) 9. triclopyr + clopyralid (Redeem) 1. 2,4-D + picloram (Grazon P+D, HiredHand, GunSlinger) 11. fluroxypyr + picloram (Surmount) Herbicide Options (cont.) 13. aminopyralid (Milestone) 14. aminopyralid + 2,4-D (ForeFront) 15. aminopyralid + metsulfuron (Chaparral) 16. Nicosulfuron + metsulfuron (Pastora) 1. metsulfuron (Cimarron, MSM E.Pro, others) 18. metsulfuron + chlorsulfuron (Cimarron Plus) 19. metsulfuron + 2,4-D + dicamba (Cimarron MAX) 2. hexazinone (Velpar) 21. sulfosulfuron (OutRider) 22. pendimethalin Prowl H 2 O 23. tebuthiuron (Spike) 24. paraquat (Gramoxone Inteon, Firestorm, Parazone) 25. glyphosate (Roundup PowerMax, others) 12. fluroxypyr + triclopyr (PastureGard) Newest Herbicides PastureGard - fluroxypyr + triclopyr (Remedy) Surmount fluroxypyr + picloram Milestone aminopyralid ForeFront aminopyralid + 2,4-D Chaparral aminopyralid + metsulfuron OutRider sulfosulfuron Prowl H 2 O pendimethalin Pastora - nicosulfuron + metsulfuron 2 PastureGard 1.5 lbs./gal. triclopyr ester +.5 lbs./gal. fluroxypyr ester Controls numerous brush species and broadleaf weeds. Upright blackberry, sweet gums, Sericea lespedeza, dogfennel, gallberry, rose species, lantana Palmetto and yucca use 2.% v/v solution in water Fair control of horsenettle and tropical soda apple Also has activity on maypop passionflower 28 Reseeding Restrictions PastureGard Cool-season grasses and small grains - 21 days Clover and other legumes 3 days Other crops 12 days Labeled for use on permanent grass forage systems This includes permanent pastures that are overseeded with winter forages. 29 Surmount 1.19 lbs./gal. picloram amine +.96 lbs. gal. fluroxypyr amine Controls broadleaf weeds, horsenettle, tropical soda apple, and pricklypear cactus. Apply 3 to 4. pts./acre for prickly pear cactus in fall months, control is very slow, about 2 yrs. About 3 d residual control Excellent control of upright-growing blackberry (3 to 4 pts./acre) 3 5

6 21 Georgia Grazing School: Reseeding Restrictions Surmount Surmount- It s Good - BUT!!!!! Cool-season grasses - 21 days Clovers 12 months Other legumes 12 months 31 Do not use hay from treated areas for compost or mulch transfer livestock to untreated areas without d cleanout use manure for fertilizing broadleaf crops use in any temporary forage system involving broadleaf crops USE ONLY ON PERMANENT GRASS FORAGE SYSTEMS 32 Milestone Milestone 2. lbs./gal. aminopyralid Use rate: 4. to. fl. ozs./acre Numerous broadleaf weeds thistles, horsenettle, tropical soda apple, buttercup Do not seed legumes year of application (additional research being conducted) Delay application until grasses have 4 to 5 leaves. Non-volatile Injurious to legumes No grazing or hay restriction for any type of livestock Weak on sida species, dogfennel, plantains, blackberry, wild radish, other mustards. Add 2,4-D or Remedy for weeds above ForeFront.33 lbs./gal. aminopyralid lbs./gal 2,4-D Use rate: 1.5 to 2.6 pts./acre Numerous broadleaf weeds thistles, horsenettle, buttercup, henbit, plantains, verbena Do not seed legumes year of application (additional research being conducted) Delay application until grasses have 4 to 5 ForeFront Injurious to legumes No grazing restriction for any type of livestock. day hay harvest restriction Better control of plantains and common pokeweed than Milestone leaves

7 21 Georgia Grazing School: Chaparral Bermuda, orchardgrass, tall fescue (up to 2. oz/a Native grasses wheatgrass, bluestems, grama Apply to fully tillered or established Same tall fescue precautions as metsulfuron products (2 yr establishment) Chaparral Rate (oz. product/a) Act. Ingredient * 3. aminopyralid metsulfuron *Chaparral at 2. oz./a = 4. fl. oz/a of Milestone 2SC +.3 oz/a Metsulfuron 6DG 3 38 Chaparral Aminopyralid- It s Good - BUT!!!!! Non-volatile Injurious to legumes Do not seed legumes year of application (additional research being conducted) 39 Do not use hay from treated areas for compost or mulch transfer livestock to untreated areas without 3 d cleanout use manure for fertilizing broadleaf crops use in any temporary forage system involving broadleaf crops USE ONLY ON PERMANENT GRASS FORAGE SYSTEMS 4 Grass Control Options - Bermudagrass Dormant bermuda Glyphosate 1. pt./acre (4. lb./gal.) Gramoxone Inteon 1. to 2. pts./acre Active Growth Bermuda Pensacola bahiagrass Cimarron, Chaparral, Impose Smutgrass Velpar Annual grasses Roundup PowerMax, after first hay cut Impose (imazapic) Johnsongrass OutRider, Impose Spot treat or ropewick glyphosate Prowl H 2 - BASF Pendimethalin Preemergence herbicide: 3.2 to 4.2 qts/acre Needs rainfall for incorporation within 3 days of application Labeled on dormant forage bermudagrass hay or pasture (NOT LABELED ON TALL FESCUE) 45 day hay harvest restriction 6 day grazing restriction all livestock types See supplemental label at: 42

8 21 Georgia Grazing School: Prowl H 2 - BASF PRE control of crabgrass, goosegrass, sandbur, Texas and fall panicum Also controls some annual broadleaf weeds such as pigweed Apply February to early March to dormant bermudagrass Must be applied before annual grasses germinate (crabgrass begins germination at soil temps. of 5 to 55 F.) 43 Stand Density, % Prowl H 2 on the Stand Density of Irrigated Tifton 85 Pasture. Wrens. Control Prowl H2 2. lb./a Applications made to dormant bermudagrass on 3/5/1. 6/16/1 /22/1 Prowl H2 3. lb./a Prowl H2 4. lb./a Prowl H 2 on Crabgrass Control in Irrigated Tifton 85 Pastures. Wrens. Pastora DuPont - 21 Sulfonylurea Nicosulfuron 56.2% + Metsulfuron 15.% Pastora controls: Sandbur, panicum sp., foxtails, barnyardgrass, signalgrass < 2. in. tall Pensacola bahiagrass, before seedheads emerge in spring Vaseygrass (after hay cutting) Italian ryegrass < 6. in. tall Johnsongrass 6 to 1 in. tall annual broadleaf weeds < 4. in. tall Applications made to dormant bermudagrass on 3/5/1. Pastora DuPont - 21 Use rates: 1. to 1.5 oz./acre + NIS Will be used on bermudagrass only (injures tall fescue and legumes) No grazing or haying restrictions Rotation Intervals Wheat, ryegrass, fescue 4 months Oat, barley 1 months Legumes 12 months Effect of Pastora Applied during Greenup on Southern Crabgrass Control. 29. (Oz/ac) Pastora applied Apr. 15, 29 seedling crabgrass 8

9 21 Georgia Grazing School: Effect of Pastora Applied mid-july on Southern Crabgrass Control. 29. Effect of Pastora on Spring Growth of Irrigated Tifton 85 Pasture after A. Ryegrass Removal. Wrens (Oz/ac) Stand Density, % /2/1 6/16/1 8/24/1 Pastora applied July 2, 29 multi-tillered crabgrass Control Pastora 1. oz./a Pastora 1.5 oz./a Pastora 1. oz./a + 1. oz./ a (2 d) Applications made on 5/6/1 and 5/2/1 for the 2 day reapplication treatment. Control of annual ryegrass was 1% with Pastora. Control % Effect of Pastora on Goosegrass Control in Irrigated Tifton 85 Pasture. Wrens /2/1 6/16/1 8/24/1 Control Pastora 1. oz./a Pastora 1.5 oz./a Pastora 1. oz./a + 1. oz./ a (2 d) Applications made on 5/6/1 and 5/2/1 for the 2 day reapplication treatment. Conclusions - Pastora Will control Italian ryegrass Crabgrass not as sensitive as other annual grasses (best control of crabgrass is at seedling stage) Established bermudagrass (one growing season) Application Timings Winter dormant bermuda Spring before 2 inches of new growth Summer within days of hay cutting Thistle Control Thistle Too late to spray bull thistle Treat at this stage musk thistle 53 Late fall or early spring application Treat at rosette leaf stage 2,4-D ester WeedMaster Grazon P+D Chaparral ForeFront Milestone Pastora 54 9

10 21 Georgia Grazing School: Blackberry 1% Remedy or PastureGard for spray to wet. 2-3 pints per acre for broadcast. Metsulfuron.5 oz per acre Spray at full bloom. Repeat applications needed for complete control. Blackberry Control Treatment Rate % Control 1 year later Grazon P+D + 1% +.25% 3 Remedy PastureGard 1% 8 Remedy 1% 9 Milestone.5% June 25 to June 26 Faulkner County, AR 56 Blackberry control with Remedy, 1 qt/ac, Fall application, 6 MAT 5 Blackberry control with Cimarron Plus.5 ozs/ac at bloom 5 MAT 58 Dewberry Dewberry.625 oz Cimarron Plus per acre. Spray at full bloom

11 21 Georgia Grazing School: Greenbrier Control Treatment Rate % Control 1 yr later PastureGard 2% 2 Remedy 2% Milestone.5% Perennial seed, roots Treat at 18 to 24 inch growth stage Best PastureGard, Remedy, Grazon P +D, Weedmaster Good 2,4-D, 2. qts./acre Poor to Fair Metsulfuron Dogfennel J.W. Boyd, AR Hemp Dogbane Very tough to control. Surmount at 3 to 6 pts per acre is the best. Remedy provides temporary burn down. Horsenettle Milky juice Pigweed Horsenettle Best Grazon P+D at 3. pts./acre or ForeFront at 2.6 pts/ac Fair WeedMaster at 4. pt./ acre or 2,4-D at 3 pts/ac Add a nonionic surfactant at.25% v/v. Apply at mid-bloom through fruiting Treat when small (2 to 4 inches) early May Metsulfuron.25 to.33 oz/acre Grazon P+D, Weedmaster, 2,4-D pts/acre, Cimarron Max 1 pt +.25 oz Germinates all summer. Repeat applications needed. Pigweed seed

12 21 Georgia Grazing School: Keys to Herbicide Use Spiny amaranth 6 68 Incorporate Mowing Grazing Fertilization Herbicides???????? in an integrated approach to weed management 69 12