Presentation on theme: "Weed Management in Pastures - 2007 Dr. Tim Murphy, Extension Weed Specialist The University of Georgia used with permission Georgia Agricultural Education."— Presentation transcript:
Weed Management in Pastures Dr. Tim Murphy, Extension Weed Specialist The University of Georgia used with permission Georgia Agricultural Education Curriculum Office June 2007
Pasture Weed Issues Lack of management - fertility, lime, mowing, overgrazing Only 15% of Georgia pastures are sprayed on annual basis Grazing restrictions Legume tolerance
Do I spray or fertilize first? Spray first Control existing weeds Begin soil-test based lime and fertilizer program Establish legumes after good weed control has been practiced for 1 to 2 years
Forage Response to Weed Control and Fertilizer (TAMU; Wet Year) Bade, TAES
Fertility Examples for the Southeast Broomsedge General indicator of low pH (<5.4), low P and low K Affected by grazing Sericea lespedeza Extremely tolerant of low pH, P and K Bahiagrass and Common Bermudagrass More tolerant of low K than hybrid bermudagrass Also more tolerant of close grazing
Effect of Grazing on Weed Control Grazing is SELECTIVE defoliation Unlike mowing this may allow greater pressure to be placed on a single forage species Shift competitive advantage toward favorable species Can alter selectivity with animal species, stocking rate and timing
Vegetation Preferences S. Forages 3 rd Ed.
Overgrazing Overgrazing decreases root CHO of forage species, compacts soil, injures crowns, and decreases rooting depth. “Releases” unpalatable species like horsenettle Ideally want to maintain a minimum forage height Leaf area maintained - photosynthesis Improves vigor and competitive advantage for desired species Shades weed seedlings 2-3” for bermudagrass in summer months 3-4” for tall fescue Heavily grazed hybrid bermudagrass can encourage common and bahiagrass encroachment
Under grazing can also be a factor Weeds can outgrow and shade forage species
Do we really want to eliminate all weeds from pastures?
Positive Attributes of “Weeds” in Pastures 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 Chickweed, curly dock, shepherds purse and tall fescue mixture. Eatonton GA
DOES MOWING HELP?
Mowing Less effective than grazing Largely cosmetic Keeps forage in vegetative/competitive stage Possible to decrease some annual weeds IF mowed before viable seed formation Some perennials are not affected by mowing Horsenettle Timing is important Dogfennel, thistle?
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
Remedy 4.0 lbs./gal. triclopyr ester low volatility Excellent on upright blackberry, numerous broadleaf weeds Good on tropical soda apple Fair on horsenettle Poor on pokeweed, honeysuckle, trumpetcreeper
Remedy Mixes with diesel, basal oils Remedy 20% + 80% diesel, excellent as basal application for trees < 4 inch DBH, and spot control of pricklypear cactus and palmetto Injurious to clovers Apply to seedling grasses 5 to 6 inches tall or after tiller development
Remedy Grazing and haying restrictions Beef grazing - 0 dDairy grazing - 14 d Hay - 7 d (all livestock types, except lactating dairy cattle, next growing season) Slaughter - 3 d
Basal Stem Spray 1.Stems should be less than 4 inches in diameter. 2.More effective on trees with smooth bark. 3.Can be done anytime. Easiest to do during the dormant season. Mix: 80% diesel fuel or vegetable oil + 20% Remedy by volume.
Stump Treatment Treat as soon as possible after cutting. Treat as soon as possible after cutting. 80% diesel fuel + 20% Remedy 80% diesel fuel + 20% Remedy Remedy RTU is convenient, no mixing, low odor Remedy RTU is convenient, no mixing, low odor
Stump Treatment Big stump, treat perimeter Little stump, treat all
Cimarron 60DF metsulfuron DuPont is phasing out Ally brand name for pastures Effective for ‘Pensacola’ bahiagrass, spiny amaranth, curly dock, buttercup, wild garlic control, blackberry Poor horsenettle control Injurious to legumes & ryegrass (4 mo plant back)
Cimarron 0.1 to 0.3 oz. product per acre Use low rates on tall fescue and timothy Do not mix with liquid fert. for bahiagrass control 0 d grazing or haying restriction - all livestock
Cimarron Plus Two-way product 48% metsulfuron + 15% chlorsulfuron (63DF) Effective for ‘Pensacola’ bahiagrass, spiny amaranth, curly dock, buttercup, wild garlic control, blackberry, dewberry, honeysuckle Poor horsenettle control Injurious to legumes & ryegrass (4 mo plant back)
Cimarron Plus to 1.25 oz. product per acre Use < 0.5 oz. product/acre on fescue Do not mix with liquid fert. for bahiagrass control 0 d grazing or haying restriction - all livestock
Cimarron MAX Co-Pack product Metsulfuron 60DF + 2,4-D amine (2.87 lbs./gal.) + dicamba (1.0 lb./gal.) Increases number of broadleaf weeds controlled Use rates 0.25 oz./acre of Cimarron plus 1.0 to 2.0 pts./acre of 2,4-D + dicamba Add nonionic surfactant at 0.25% v/v
Cimarron MAX Grazing Restrictions Lactating dairy animals – 7 days Other livestock species – 0 days Haying Restrictions All livestock – 37 days
Grazon P+D, GunSlinger 2.0 lbs./gal. 2,4-D amine lbs./gal. picloram amine Excellent control of broadleaf weeds Excellent on horsenettle and tropical soda apple For horsenettle, use 3 pts./acre at early bloom. About 30 d residual control Fair control of blackberry
Grazon P+D, GunSlinger Injurious to clovers Apply to seedling grasses or overseeded small grains at tiller growth stage, 1.5 pts./acre or less Newly-sprigged bermuda – 1.5 pts./acre, delay until stolons are 6 inches long Beef grazing - 0 dDairy grazing - 7 d Hay - 30 d (all livestock types) Slaughter - 3 d
Reseeding Restrictions – Grazon P+D Cool-season grasses - 21 days Clover - 2 pts./acre or less Fall-seeding permitted if Grazon P+D applied no later than June (4 month plant back) Clover – 2 to 3 pts./acre Spring (Feb. – Mar.) seeding permitted the following spring for applications made no later than Sept. 15 the previous year.
Grazon P+D & GunSlinger - Good - BUT!!!!! Do not use hay from treated areas for compost or mulch transfer livestock to untreated areas without 7 d cleanout use manure for fertilizing broadleaf crops use in any temporary forage system involving broadleaf crops USE ONLY ON PERMANENT GRASS FORAGE SYSTEMS
Plateau BASF will no longer market to private landowners grass roadsides, wildflowers, noncropland sites WHY??? Economics Low sales,objections to injury Can make more money in other markets
Newly-sprigged Bermuda Direx 4L, Diuron 4L Karmex is not labeled for this use Plant sprigs 2 inches deep Apply immediately after sprigging Use 3.0 to 4.0 pts./acre Not labeled in established bermudagrass Annual grasses and broadleaf weeds 70 day grazing restriction
Overdrive - BASF Dicamba + diflufenzopyr Controls broadleaf weeds 0 day grazing or haying restriction Limited data base Primarily will be marketed for rights-of-way use
PastureGard 1.5 lbs./gal. triclopyr ester 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 2.0% v/v solution in water Fair control of horsenettle and tropical soda apple Also has activity on maypop passionflower
PastureGard Mixes with diesel and other oil carriers PastureGard 50% + 50% diesel, excellent as basal application for trees < 4 inch DBH Injurious to clovers Apply to seedling grasses after tiller development
PastureGard Beef and other livestock grazing - 0 d Dairy grazing – not permitted during the growing season of application Hay – 14 d (all livestock types)
Reseeding Restrictions – PastureGard Cool-season grasses and small grains - 21 days Clover and other legumes – 30 days Other crops – 120 days Labeled for use on permanent grass forage systems This includes permanent pastures that are overseeded with winter forages.
Surmount 1.19 lbs./gal. picloram amine lbs. gal. fluroxypyr amine Controls broadleaf weeds, horsenettle, tropical soda apple, and pricklypear cactus. Apply 3 to 4.0 pts./acre for prickly pear cactus in fall months, control is very slow, about 2 yrs. About 30 d residual control Excellent control of upright-growing blackberry (3 to 4 pts./acre)
Surmount Injurious to clovers Apply to seedling grasses or overseeded small grains at tiller growth stage Newly-sprigged bermuda –delay until stolons are 6 inches long Beef grazing - 0 d; slaughter 3 d Lactating Dairy Animals – grazing 14 d; silage 14 d. Hay – 7 d (all livestock types)
Surmount- It’s Good - BUT!!!!! Do not use hay from treated areas for compost or mulch transfer livestock to untreated areas without 7 d cleanout use manure for fertilizing broadleaf crops use in any temporary forage system involving broadleaf crops USE ONLY ON PERMANENT GRASS FORAGE SYSTEMS
Milestone 2.0 lbs./gal. aminopyralid Use rate: 4.0 to 7.0 fl. ozs./acre Numerous broadleaf weeds – thistles, horsenettle, buttercup Do not seed legumes year of application (additional research being conducted) Delay application until grasses have 4 to 5 leaves.
Milestone 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 0.33 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 leaves.
ForeFront Injurious to legumes No grazing restriction for any type of livestock. 7 day hay harvest restriction Better control of plantains and common pokeweed than Milestone
Comparison of Grazon P+D, Surmount, PastureGard, Milestone and Forefront HerbicideActive Ingredient Grazon P+D, GunSlinger2,4-Dpicloram Surmountfluroxypyrpicloram PastureGardfluroxypyrtriclopyr Milestoneaminopyralid Forefrontaminopyralid2,4-D
Comparison of Grazon P+D, Surmount and PastureGard, Milestone and ForeFront Weed Grazon P+D SurmountPastureGardMilestone Fore- Front ButtercupEGFG-EE BlackberryP-FEEPP DogfennelG-EEEFF-G HorsenettleGG-EFEE HorseweedEEGEE PricklypearF-GEFPP
Maverick - Monsanto Sulfosulfuron, 75WDG Section 18 in GA, AL, MS, AR, OK, LA APPROVED FOR 2007 Controls johnsongrass and sedges in bermudagrass and bahiagrass Use rate – 1.33 ozs./acre Add a nonionic surfactant at 0.25% v/v.
Maverick - Monsanto Johnsongrass 18 to 24 inches tall, up to seedhead stage of growth Nutsedges – 4 to 8 inches tall Does not control annual grasses, vaseygrass, dallisgrass, smutgrass, etc. Tank-mix with other herbicides for broadleaf weed control
Maverick - Monsanto Grazing and haying restriction 14 days – all livestock types Treated fields may be rotated only to wheat. Injurious to clovers.
When do you spray? Winter annuals - henbit, chickweed, buttercups, thistles, wild radish (turnips) November through March Grass and Small Grain Forages Delay application until the 4 to 5 leaf growth stage
Tolerance of 2- to 4-Leaf Wheat to Herbicides 2,4-D (1 and 2 pt. rates) Weedmaster (1, 2 and 4 pt. rates) Grazon P+D (1, 2 and 4 pt. rates) Sprayed in mid-December 2- to 4-leaf wheat
2,4-D Amines and esters Delay application until grasses have 4 to 5 leaves For grain production delay appl. until fully tillered Use up to 2.0 pts./acre, except on oats use 1.0 pt./acre Weak on chickweed and henbit Good on buttercup, wild radish and other mustards
2,4-D Grazing and haying restrictions varies by product Weedar 64 Beef cattle – 0 days Lactating dairy animals – 7 days Hay – all types – 30 days
WeedMaster 2.87 lbs. 2,4-D lb. dicamba per gallon Delay application until grasses have 4 to 5 leaves Use up to 2.0 pts./acre, except on oats use 1.0 pt./acre Better than 2,4-D on chickweed and henbit Grazing restrictions: only lactating dairy cows – 7 days Hay/silage: 37 days, all livestock types
Summary - Forage Weed Control Know cropping system Use approved cultural practices Identify weeds Select product Follow grazing and haying restrictions Proper application timing
Summary Poor fertility and overgrazing are huge contributors to weed problems Long term solutions will have to address these issues Improving fertility and grazing management of mediocre stands may revive them Process likely slow vs herbicides Mowing can help