Successful Tall Fescue Pasture Weed Management A Year-Round Commitment / Challenge

Transcription

1 Successful Tall Fescue Pasture Weed Management A Year-Round Commitment / Challenge Travis W. Gannon, PhD North Carolina State University Department of Crop Science

2 Topics for Discussion Importance of weed control Herbicide application timing to ensure efficacy Current herbicide options Specific weed control Fencerow weed control Aminopyralid, clopyralid, picloram carryover issues New herbicides Weed control calendar

3 Topics for Discussion Lack of management inputs (fertility, lime, mowing, overgrazing, etc.) 2,4-D is not the only herbicide available Restriction of clover plantings or mixes

4 Legume Tolerance Many forage producers like their stands to consist of a grass / clover mixture. Because of the clover, the only herbicides labeled for this mixture are 2,4-D (1 to 2 pt/a) and Aim (2 fl oz/a). There are lots of common broadleaf weeds not controlled by these two herbicides.

5 Importance of pasture weed control Maintain a pure monoculture or stand over time, weakens grass base Competition with desired species reducing yield and quality Hay harvesting and quality Some weeds are noxious and/or poisonous Some are nitrate accumulators

6 Importance of pasture weed control Grass Weeds Interfere when striving for pure stands (horse owners, hog waste producers) Interfere with hay drying Generally not a health concern except johnsongrass Broadleaf Weeds Numerous, noxious, toxic, prickly (animals will not graze)

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9 Plants Poisonous to Horses Showy crotalaria Sweet clover Groundsel Black cherry White snakeroot Black locust Black nightshade Horsenettle Casterbean Poison hemlock Marijuana Bitter sneezeweed Bracken fern Red buckeye Butterfly milkweed Hemp dogbane Lantana Red maple Mustard species Perilla mint Pokeweed

10 Plants Poisonous to Cattle Showy crotalaria Sweet clover Black locust Black cherry White snakeroot Brackenfern Choke cherry Black nightshade Horsenettle Ground-cherry Poison hemlock Butterfly milkweed Jimsonweed Pigweed spp. Cocklebur Buttercup spp. Milkweed species Bitter sneezeweed Sicklepod Hemp dogbane Lantana Hemp sesbania Mustard species Perilla mint Red maple Casterbean Pokeweed Red buckeye Marijuana Cherry laurel Casterbean Coffee senna Johnsongrass

11 Advantages to scouting, early weed identification and treatment Can control before desired crop gets thinned out Less herbicide usually needed for control of younger plants (save money) Herbicide may not control mature plants regardless of rate (henbit, Italian ryegrass; curly dock) Herbicides do not kill weed seeds (you may kill the parent plant, but offspring will be unaffected)

12 The Key to Pasture Weed Management? Effectively controlling weedy species to remove weed competition

13 The Key to Pasture Weed Management? Including winter and summer weeds

14 The Key to Pasture Weed Management? Acknowledging this may not be accomplished with ONE herbicide at any ONE given time!

15 Current herbicide options

16 Tall Fescue Pasture Grass Herbicides Trade name Roundup Active ingredient(s) glyphosate

17 Tall Fescue Pasture Broadleaf Herbicides Trade name Active ingredient(s) 2,4-D 2,4-D amine or ester Aim carfentrazone Banvel dicamba amine Chaparral*** metsulfuron + aminopyralid Cimarron Plus*** metsulfuron + chlorsulfuron Cimarron Max*** metsulfuron + 2,4-D amine + dicamba amine *** Tall fescue stand must be at least 2 yrs expect injury

18 Tall Fescue Pasture Broadleaf Herbicides Trade name Crossbow Curtail ForeFront R&P Grazon P+D Milestone Overdrive Active ingredient(s) 2,4-D ester + triclopyr ester 2,4-D amine + clopyralid amine aminopyralid + 2,4-D amine picloram amine + 2,4-D amine aminopyralid diflufenzopyr + dicamba

19 Tall Fescue Pasture Broadleaf Herbicides Trade name PastureGard Rage D-Tech Redeem R&P Remedy Ultra Surmount Weedmaster Active ingredient(s) triclopyr ester + fluroxypyr ester carfentrazone + 2,4-D ester triclopyr amine + clopyralid amine triclopyr ester picloram amine + fluroxypyr ester 2,4-D amine + dicamba amine

20 Pasture Broadleaf Herbicide Restrictions Beef Grazing Dairy Grazing Slaughter Hay Sensitive crop transfer 2,4-D Aim Banvel Chapparal Cim. Plus Cim. Max Crossbow *** *** 365 day hay restriction for lactating dairy animals

21 Pasture Broadleaf Herbicide Restrictions Beef Grazing Dairy Grazing Slaughter Hay Sensitive crop transfer Curtail ForeFront Grazon P+D Milestone PastureGard Rage D-Tech Redeem *** 7 *** 365 day hay restriction for lactating dairy animals

22 Pasture Broadleaf Herbicide Restrictions Beef Grazing Dairy Grazing Slaughter Hay Sensitive crop transfer Remedy 0 1 season Surmount Weedmaster

23 Specific problem weeds and control Crabgrass species Goosegrass Foxtail sp. Yellow crownsbeard Henbit Catsear dandelion Bitter sneezeweed Dogfennel Wild garlic Sericea lespedeza Plantain sp. Johnsongrass

24 Crabgrass species Summer annual grass No selective herbicide available

25 Goosegrass Summer annual grass No selective herbicide available

26 Foxtail species Summer annual grass No selective herbicide available

27 Johnsongrass Summer annual/warm-season perennial No selective herbicide available - Spot treat or wipe with glyphosate

28 Yellow crownbeard warm season perennial Grazon P+D 1.5 qt/acre Banvel, ForeFront, Surmount, Weedmaster (1 qt/acre) Redeem R&P 1-2 qt/a Milestone pt/acre

29 Henbit winter annual broadleaf Milestone pt/acre Banvel 1 pt/acre Weedmaster 1.5 pt/acre preflower 3 pt/acre flower ForeFront 1 qt/acre Crossbow 3 qt/acre

30 Thistle Control perennial, biennial Late fall or early spring application Treat at rosette leaf stage Crossbow 4 qt/acre; Curtail 3 qt/acre 2,4-D ester - 2 qt/acre Grazon P+D 1.5 qt/acre Banvel, ForeFront, Surmount, Weedmaster (1 qt/acre) Redeem R&P 1 qt/a biennials, 2 qt/a perennials Milestone pt/acre

31 Buttercup species: perennial broadleaf Weedmaster 1 to 3 pt (preflower to late bloom) 2,4-D amine 2 pt/acre; Grazon P+D 3 pt/acre Redeem R&P 2.5 pt/acre Crossbow 1 qt/acre annuals, 3 qt/acre perennials Milestone pt/acre; ForeFront 2 pt/acre

32 Catsear dandelion perennial 2,4-D amine 2 pt Crossbow 1-2 qt ForeFront 2 pt Grazon P+D 3 pt Milestone pt Redeem R&P 2.5 pt Weedmaster 1-3 pt

33 Bitter Sneezeweed Summer annual Banvel 1 qt/a Crossbow 1-2 qt/a Forefront 1 qt/a Grazon 1.5 qt/a Milestone pt/a Weedmaster 1.5 pt/a

34 Dogfennel Warm season perennial 2,4-D 2 qt/a Banvel 1 qt/a Crossbow 1-2 qt/a Grazon 1.5 qt/a PastureGard 3 pt/a Redeem 1-2 pt/a Remedy 1 qt/a Weedmaster 1.5 pt/a

35 Wild garlic: clump forming perennial Fall applications are best. Feb - Mar application of 2,4-D amine 3 qt/acre (add 0.25% NIS)

36 Sericea lespedeza Perennial, semiwoody Crossbow 1-2 qt/a Grazon 1.5 qt/a PastureGard 3 pt/a Redeem 1-2 pt/a Remedy 1 qt/a

37 Plantain species: perennial broadleaves Banvel, Redeem R&P, Remedy, Weedmaster - 2 pt ForeFront, PastureGard 2.5 pt 2,4-D amine, Grazon P+D 3 pt Crossbow, Curtail 3 qt

38 White clover: perennial broadleaf ForeFront, Surmount, Weedmaster (1.5 pt/acre) Banvel, Redeem R&P, Remedy (1 qt/acre) PastureGard 2.5 pt/acre; Grazon P+D 3 pt/acre Curtail 2 qt/acre; Crossbow 3 qt/acre Cimarron Plus to oz/acre; Overdrive 8 oz/a Cimarron Max 0.5 oz + 2 pt/acre; Chaparral 1.75 oz/a

39 Banvel, Chaparral Cimarron Forms. Crossbow, Forefront Grazon, Milestone Overdrive, Redeem Remedy Ultra, Surmount Weedar, Weedmaster Horsenettle

40 Banvel, Chaparral Cimarron Forms. Crossbow, Curtail Forefront, Grazon Milestone, Outrider Overdrive, PastureGard Rage D-Tech, Redeem Remedy Ultra, Surmount Telar, Weedar, Weedmaster Horseweed

41 Cimarron depends on form. Grazon 4pt/a Remedy Ultra 1 qt/a Remedy Ultra + Grazon pt/a Surmount 3-4 pt Blackberry

42 Banvel 1-2% v/v Cimarron depends on form. Crossbow 1-1.5% v/v Glyphosate 1% v/v Grazon 4 qt/a Multiflora Rose

43 Fencerow weed control soft bareground 2 qt/a Roundup + 1 lb ai/a Barricade lb ai/a simazine (optional)

44 Objective #2: Determine the effect of simulated herbicide drift into non-target areas. Aminocyclopyrachlor (AMCP) Recently registered synthetic auxin herbicide Thought to possess more favorable environmental profile Highly active compound Widely used in cool-season turf Limited e-fate and off-target research available

45 Objective #2: Determine the effect of simulated herbicide drift into non-target areas. Aminocyclopyrachlor (AMCP) Recently registered synthetic auxin herbicide Thought to possess more favorable environmental profile Highly active compound Widely used in cool-season turf Limited e-fate and off-target research available

46 x Implications

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48 Dow Agro Gannon - CS725 (pest. chem.)

49 Gannon - CS725 (pest. chem.)

50 Clopyralid Aminopyralid Picloram Redeem, Curtail Milestone, Forefront, Chaparral Grazon P+D, Surmount Plant Residue and Manure Concerns!!!!! Excellent broadleaf weed herbicides labeled for pastures Super sensitive to beans, peas, lentils, potatoes, various other legumes, ornamental and orchard plants

51 Mulch under bean plants containing a pyridine herbicide

52 Mulch under pepper plants containing a pyridine herbicide

53 Clopyralid Aminopyralid Picloram Redeem, Curtail Milestone, Forefront, Chaparral Grazon P+D, Surmount Do not rotate to cropland for 1 year after application Do not plant broadleaf crop until field bioassay conducted Field bioassay: plant short test rows in treated area and observe symptoms if none present, then plant Do not use treated hay or straw in compost or mulch Do not use or spread manure to broadleaf crops if animal has grazed or been fed treated hay within 3 to 7 days Animal transfer: 3 to 7 days if taking to broadleaf crop area

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55 xx Dow Agro Gannon - CS725 (pest. chem.)

56 Clopyralid Aminopyralid Picloram Redeem, Curtail Milestone, Forefront, Chaparral Grazon P+D, Surmount To promote herbicide decomposition, plant residues should be evenly incorporated in soil surface or burned. Aminopyralid breakdown in plant residues or manure is more rapid under warm, moist soil conditions and may be accelerated by supplemental irrigation.

57 Fall Seeded / Overseeded Grasses If spraying before seeding Wait 3 to 4 weeks before seeding (check specific labels for accuracy of statement) If spraying after seeding Wait until seedlings get 6 inches of growth and begin tillering (check specific labels) usually spring

58 Herbicides Labeled for Pasture Seedlings Banvel [4] Up to 1 pint/a for new seedlings Weedmaster Up to 2 pint/a for new seedlings [4+4] 2 to 4 pint/a for new stolons Broadleaf weed control only

59 JANUARY - MARCH Weed Management Options

60 Postemergence Weed Control in Hay Crops (Winter Annuals and Cool Season Perennials) Late Dec to early March is usually not a good time to treat for winter weed control.

61 APRIL JUNE Weed Management Options

62 Apr Jun Weed Control Possibilities Winter Weeds Waited too late to spray as far as reducing weed seed supply and reducing future winter weed stands Can open up fescue stand to keep from completely choking out (unless summer weed problems exist)

63 Apr Jun Weed Control Possibilities Summer Weeds Identify early and spray early!!! Can open up fescue stand to keep from completely choking out Fescue not heat / drought stressed Apr Jun as compared to Jul Sep and will recover quicker

64 JULY SEPTEMBER Weed Management Options

65 Problems With July - September Applications Weeds already reproduced (tillers, tubers, seedheads) Higher herbicide rates needed for adequate control Weeds hardened, woody, more difficult to control Many herbicides not recommended > 90 F and dry Volatility concerns Weeds not actively growing when very hot and dry

66 OCTOBER - DECEMBER Weed Management Options

67 Postemergence Weed Control in Hay Crops (Winter Annuals and Cool Season Perennials) Best time to control (usually*) is Oct through Dec Weeds are young, actively growing, no seeds!!! *Germination depends on rainfall could be dry, grass canopy, other factors A good time to control is late-march through Apr* Winter weeds begin their final growth spurt * Don t wait too late by letting weeds go to seed!

68 Weed control with aminocyclopyrachlor (AMCP) AMCP is a new herbicide being developed by DuPont for pastures and other areas Controls many broadleaf weeds Will be offered in combination with 2,4-D or metsulfuron Expected to be commercially-available in 2013