Successful Tall Fescue Pasture Weed

Management – A Year-Round

Commitment / Challenge

Travis W. Gannon, PhD North Carolina State University

Department of Crop Science

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

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

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.

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

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)

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

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

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)

The Key to Pasture Weed Management?

Effectively controlling weedy

species to remove weed competition

The Key to Pasture Weed Management?

Including winter and

summer weeds

The Key to Pasture Weed Management?

Acknowledging this may not

be accomplished with ONE

herbicide at any ONE given

time!

Current herbicide options

Tall Fescue Pasture Grass Herbicides

Trade name Active ingredient(s)

Roundup glyphosate

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

Tall Fescue Pasture Broadleaf Herbicides

Trade name Active ingredient(s)

Crossbow 2,4-D ester + triclopyr ester

Curtail 2,4-D amine + clopyralid amine

ForeFront R&P aminopyralid + 2,4-D amine

Grazon P+D picloram amine + 2,4-D amine

Milestone aminopyralid

Overdrive diflufenzopyr + dicamba

Tall Fescue Pasture Broadleaf Herbicides

Trade name Active ingredient(s)

PastureGard triclopyr ester + fluroxypyr ester

Rage D-Tech carfentrazone + 2,4-D ester

Redeem R&P triclopyr amine + clopyralid amine

Remedy Ultra triclopyr ester

Surmount picloram amine + fluroxypyr ester

Weedmaster 2,4-D amine + dicamba amine

Pasture Broadleaf Herbicide Restrictions

Beef

Grazing

Dairy

Grazing

Slaughter Hay Sensitive

crop

transfer

2,4-D 0 7 3 30 0

Aim 0 0 0 0 0

Banvel 0 7 - 40 30 37 - 90 0

Chapparal 0 0 0 0 3

Cim. Plus 0 0 0 0 0

Cim. Max 0 7 30 37 0

Crossbow 0 14 3 7 0***

*** 365 day hay restriction for lactating dairy animals

Pasture Broadleaf Herbicide Restrictions

Beef

Grazing

Dairy

Grazing

Slaughter Hay Sensitive

crop

transfer

Curtail 0 14 7 30 7

ForeFront 0 0 0 7 3

Grazon P+D 0 7 3 30 7

Milestone 0 0 0 0 3

PastureGard 0 365 3 14 0

Rage D-Tech 0 7 3 30 0

Redeem 0 14 3 7*** 7

*** 365 day hay restriction for lactating dairy animals

Pasture Broadleaf Herbicide Restrictions

Beef

Grazing

Dairy

Grazing

Slaughter Hay Sensitive

crop

transfer

Remedy 0 1 season 3 14 0

Surmount 0 14 3 7 7

Weedmaster 0 7 30 37 0

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

Crabgrass species

Summer annual grass

No selective

herbicide available

Goosegrass

Summer annual grass

No selective

herbicide available

Foxtail species

Summer annual grass

No selective

herbicide available

Johnsongrass

Summer annual/warm-season perennial

No selective

herbicide available

- Spot treat or wipe

with glyphosate

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 – 0.375 pt/acre

Henbit winter annual broadleaf Milestone - 0.375 pt/acre Banvel – 1 pt/acre Weedmaster 1.5 pt/acre preflower 3 pt/acre flower ForeFront – 1 qt/acre Crossbow – 3 qt/acre

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 – 0.375 pt/acre

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 – 0.375 pt/acre; ForeFront – 2 pt/acre

Catsear dandelion

perennial

2,4-D amine – 2 pt Crossbow – 1-2 qt ForeFront – 2 pt Grazon P+D – 3 pt Milestone – 0.375 pt Redeem R&P – 2.5 pt Weedmaster – 1 - 3 pt

Bitter Sneezeweed

Summer annual

Banvel – 1 qt/a

Crossbow – 1-2 qt/a

Forefront – 1 qt/a

Grazon – 1.5 qt/a

Milestone – 0.375 pt/a

Weedmaster – 1.5 pt/a

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

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

Sericea lespedeza

Perennial, semi-

woody

Crossbow – 1-2 qt/a

Grazon – 1.5 qt/a

PastureGard – 3 pt/a

Redeem – 1-2 pt/a

Remedy – 1 qt/a

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

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 – 0.375 to 0.625 oz/acre; Overdrive – 8 oz/A Cimarron Max – 0.5 oz + 2 pt/acre; Chaparral – 1.75 oz/A

Horsenettle

Banvel, Chaparral

Cimarron Forms.

Crossbow, Forefront

Grazon, Milestone

Overdrive, Redeem

Remedy Ultra, Surmount

Weedar, Weedmaster

Horseweed

Banvel, Chaparral

Cimarron Forms.

Crossbow, Curtail

Forefront, Grazon

Milestone, Outrider

Overdrive, PastureGard

Rage D-Tech, Redeem

Remedy Ultra, Surmount

Telar, Weedar, Weedmaster

Blackberry

Cimarron – depends on form.

Grazon – 4pt/a

Remedy Ultra – 1 qt/a

Remedy Ultra + Grazon –

1.5 + 3 pt/a

Surmount – 3-4 pt

Multiflora Rose

Banvel – 1-2% v/v

Cimarron – depends on form.

Crossbow – 1-1.5% v/v

Glyphosate – 1% v/v

Grazon – 4 qt/a

Fencerow weed control – soft bareground

2 qt/a Roundup +

1 lb ai/a Barricade +

1 – 2 lb ai/a simazine (optional)

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

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

Implications

• x

Gannon - CS725 (pest. chem.) Gannon - CS725 (pest. chem.)

Dow Agro

Gannon - CS725 (pest. chem.) Gannon - CS725 (pest. chem.)

Clopyralid Redeem, Curtail Aminopyralid Milestone, Forefront, Chaparral

Picloram Grazon P+D, Surmount

Excellent broadleaf weed herbicides labeled for pastures

Super sensitive to beans, peas, lentils, potatoes, various other legumes, ornamental and orchard plants

Plant Residue and Manure Concerns!!!!!

Mulch under bean plants containing a pyridine herbicide

Mulch under pepper plants containing a pyridine herbicide

Clopyralid Redeem, Curtail Aminopyralid Milestone, Forefront, Chaparral

Picloram 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

• xx

Gannon - CS725 (pest. chem.)

Dow Agro

Clopyralid Redeem, Curtail Aminopyralid Milestone, Forefront, Chaparral

Picloram 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.

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

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

JANUARY - MARCH

Weed Management Options

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.

APRIL – JUNE Weed Management Options

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)

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

JULY – SEPTEMBER

Weed Management Options

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

OCTOBER - DECEMBER

Weed Management Options

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!

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