Broadleaf Weed Control in Pastures

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Broadleaf Weed Control in Pastures

• Chemical
• and
• Non Chemical

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Why control weeds in pastures
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Life Cycle

• Annual Seed germinates, plant grows, flowers and
  seeds out in one growing season (crabgrass)
• Biennial Seed germinates, plant grows, then
  reproduces in following year (onion)
• Perennial Seed germinates, and plant lives and
  reproduces for several years (bermudagrass)

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Broadleaf plant structure
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Keys to broadleaf weed persistence

• Seed crop size
• Seed hardness
• Nutrient Reserve in the tap root
• Defenses (resistance to grazing)

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Weed Control Methods

• Chemical
• Mechanical
• Biological
• Crop Competition
• Crop Rotation
• Fire

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Mechanical Weed Control

• Burial
• Cultivation
• Mowing

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Biological

• Defoliation, desiccation of disease
• Insect No known control
• Mammals Possible

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Crop Competition

• Long term solution
• Often the most economical
• Requires compatible and useable crops
• Maintenance of proper soil fertility levels is
  required

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Effect of N Rate, herbicide and covercrop on weed
production
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Crop Rotation

• Replacement of one crop with another
• Works best with annual crops
• Usually not economical in perennial forage crops
  (bermudagrass) but may be feasible with alfalfa
  or johnsongrass

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Fire

• Earliest recorded form of forage management
• Multiple benefits (residue removal, control of
  spring weeds, increased infiltration)
• Effective on young annual weeds
• Ineffective on many perennial weeds
• Fuel load is critical

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Fire

• Timing is critical
• May damage crop plant
• VERY RISKY, HIGH LIABILITY
• Not recommended to most producers

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Prevention

• Prevention
• Minimize soil disturbance
• Keep fence lines, feed areas, etc. mowed
• Feed purchased hay and feed in weedy areas
• Keep forage crop (system) vigorous and competitive

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Chemical weed control

• Herbicides labeled for use in Texas pastures

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RoundupGlyphosate

• Wick application
• 12 Roundup to water
• Wait 14 days after application to harvest or
  graze
• May be applied once a year prior to greenup or in
  a narrow window after hay harvesting

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2,4-D

• 1 pt. - 1 qt.
• avoid newly seeded areas
• avoid bootstage
• Use a surfactant
• Do not graze within 7 days
• Fair to poor on perennials
• White and arrowleaf clover have tolerated .5 lb
  in Feb.

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WeedMaster(2,4-D Dicamba)

• 1 pt - 1 qt
• avoid newly seeded areas
• avoid bootstage
• use a surfactant
• Do not graze within 7 days of application
• Do not graze within 30 days of slaughter
• Do not harvest for hay with 37 days of treatment

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Grazon PD(Picloram 2,4-D)

• 1 pt to 2 qts
• No grazing limitations
• Deadly on clovers, allow one year carry over
  before replanting clover.
• Dont move cattle into clover

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Ally(metsulfuron)

• 0.1 - 0.3 oz.
• use a surfactant
• bahiagrass control in bermudagrass
• Can be tank mixed with hormone herbicides
• No grazing restrictions

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Amber(Triasulfuron)

• 0.28 - 0.56 oz
• control of annual broadleaf weeds and some
  (ryegrass and bromegrass) annual grasses
• no grazing restrictions
• use a surfactant
• can be tank mixed with hormone herbicides
• has residual soil activity

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Velpar(Hexazinone)

• smutgrass control in bermudagrass and bahiagrass
• not labeled for broadleaf control in pastures
• one application per year
• do not graze or feed treated forage within 60
  days of application
• use a surfactant

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Common or Problem Weeds

• In Northeast Texas

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Goatweed

• annual, prolific seed producer
• germinates in May-June
• 1 pt, 2,4-D at 2
• 1qt 2,4-D gt10
• Mow gt 15
• Sheep

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Bitter Sneezeweed

• Annual, prolific, overgrazing
• high fertility
• 2,4-D early
• Ally, Grazon, WeedMaster late.
• somewhat tolerant of mowing

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Henbit

• Winter annual
• standing hay
• winter burn
• crop competition
• most labeled herbicides
• sheep

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Dogfennel

• Summer perennial
• somewhat resistant to mowing
• sheep or goats
• Fertility
• WeedMaster or Grazon PD

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Bullnettle

• Perennial
• Weak crop stands (Crop competition)
• Fertility
• Mowing
• Resistant to grazing
• Hormone herbicides

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Horse Nettle

• Perennial
• Resistant to grazing
• Frequent mowing
• Fertility
• WeedMaster, Grazon
• Becoming a bigger problem in NE Texas

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Buttercup

• Cool season perennial
• Very resistant to grazing. Toxic
• Rich bottomlands
• Resistant to Mowing
• WeedMaster, Grazon early (lt6)

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Berry bushes (Rubus sp.)

• Viney perennial
• Multiple species
• Resistant to grazing
• Somewhat resistant to mowing
• Fire (?)
• Ally hormone
• attractive fruit crop

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Milkweeds

• thick rooted, summer perennial
• multiple species
• resistant to defoliation
• Huge Nutrient Reserve
• early application of WeedMaster, Grazon
• multiple applications
• prevention