Successful Tall Fescue Pasture Weed Management – A Year-Round Commitment / Challenge Travis W. Gannon, PhD North Carolina State University Department of Crop Science
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?
Acknowledging this may not
be accomplished with ONE
herbicide at any ONE given
time!
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
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
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!!!!!
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
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
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.
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
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
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!