Weed Control by malj

VIEWS: 2 PAGES: 45

									Weed Control
   Competition
    •   Space
    •   Light
                       Weeds
    •   Nutrient
    •   Water
   Physical Damage
    • Morningglories
    • Honeyvine
      Milkweed
       Tolerance to Competition
   Weed free for 6       Weedy for 4 weeks
    weeks                  • Weed Control after
    • Tobacco canopy         weedy problem
      tolerates late            No competition
      competition
   Shallow (1 inch
    deep)
    • Reduces root          Cultivation
      damage
    • Doesn’t disturb
      herbicide placement
    • Shears of weeds
   Breaking crust
   Deep Cultivation
    • Damages roots
    • Brings up untreated      Cultivation
      soil
    • Misconception?
         Brings up moisture
          during a drought
   Shallow Cultivation    Rolling
    • Scrapes surface
    • Hills plants        Cultivators
    • Faster Speed
             Ideal Herbicide

   Controls Weeds
    • Broadleaf
    • Grasses
   No Crop Injury
   Non-persistent to cover crop or
    rotational crop
   No drift or run-off
   Safe for applicator
                  Prowl 3.3EC
                       Weed Spectrum



• Good Control                   • Poor Control
     Annual grasses                      Rhizome Johnson Grass
     Many Broadleaf                      Hairy Galinsoga
      weeds                               Common Ragweed
      • Pigweed                           Cocklebur
                                 • Suppression
                                          Morningglories
                   Application

   Rates 2 to 3.6 pts/A
   Incorporation 1 to 2 inches
    • Photosensitivity
         Possible sun breakdown
    • Suppresses germinating weed seeds
         Most in upper 2 inches
    • Crop safety
         Plant roots below treated areas
   Root & shoot inhibitor
    • Symptoms
          Root pruning      Activity & Mode of
          Stunting
   Mitotic poison
                                   Action
   Not taken up by plants
Symptoms
Symptoms
Symptoms – Phosphorus
      Deficiency
               Persistence
Can cause cover crop damage especially in dry seasons
   Weed Spectrum
    • Good Control
                               Command 3 ME
         Annual Grasses
         Most Broadleaf
          Weeds including
           • Common Ragweed
           • Hairy Galinsoga
           • Velvetleaf
Command 3 ME   • Poor Control
                    Pigweeds
                    Seedling & rhizome
                     Johnsongrass
     Application

   Rates 2 to 2.67
    pts/A
   Placement
    • Surface application
         Cover crop safety
    • Drift
   Post-transplant
    • Within 7 days after
      transplanting
Activity & Mode
   of Action
    Photosynthesis
     inhibitor
     • Damages
       Chlorophyll
     • Turns plant white
                 Persistence




   Cover crop
    damage
                               Spartan DF




   Weed Spectrum
    • Good Control
         Most Broadleaf
          Weeds Including
           • Morningglories
           • Yellow Nutsedge
Spartan DF




                Fair Control
                 • Annual grasses
                Poor Control
                 • Common Ragweed
                 • Seedling & rhizome
                   Johnsongrass
   Rates                         Application
    • (8 fl oz/A)
    • (10.1 fl oz/A)
          If Morningglories or
           nutsedge are major
           weed problems
                                     Placement
                                      • Best not
                                        incorporated
                                           Due to crop safety
                                           OK to scratch out
                                            tractor track
   Photosensitizes
   Plants actively             Activity & Mode
    take-up                        of Action
    • Exposure to sunlight
      causes membrane
      disruption
    • Susceptible plants turn
      necrotic and die
                Persistence

   Season long control
   Grass cover crops are less sensitive
                    Devrinol 50DF

   Weed Spectrum
    • Good Control
          Annual grasses
    • Fair to Poor Control
          Most Broadleaf Weeds

   Crop Safety
    • Good
                    Application

   Rate (2 lb/A)
    • Usually in combination with Tillam for
      improved broadleaf control
   Post-transplant OK
    • but pre-emergence to weeds
      Activity & Mode of activity

   Root growth inhibitor
   Persistence
    • 12 month - can cause cover crop injury
      especially when applied post-transplant
   Weed Spectrum
    • Good Control
          Annual grasses
          Nutsedge          Tillam 6E
    • Fair to Poor
      Control
          Many Broadleaf
           Weeds
    • Crop Safety
          Good
          Damage possible
           under specific
           conditions
                Application

   Rate (2.67 qt/A)
   Usually in combination with Devrinol for
    improved broadleaf control
      Activity & Mode of Activity

   Taken up by plants and translocated to
    shoots
   Has effect on meristemactic tissue
                  Persistence

   3 to 6 weeks
   Highly volatile
   Readily leached by in soil
    • Can reverse leach after rainfall
Weed Control in Burley Tobacco
Fayette Co. – David Tucker Farm
   Weed Spectrum
    • Good Control
          Annual & perennial
           grasses
    • No Control
          Broadleaf Weeds           Poast 1.53E
   Application
    • Rate
          1.5 pts/A
            + Crop oil concentrate
              (1 qt/A)
    • Post-emergence
      Activity & mode of activity

   Taken up by plants and translocated
    throughout
   Slow acting
   Persistence
    • None
Diagnosing Chemical Damage in
           Tobacco
   Look for symptom
    •   Stunting
    •   Leaf distortion
    •   Abnormal vein patterns
    •   Discoloration
   Look for possible sources of chemical exposure
    • Drift
            Other crops near by
            Right of ways
    • Contaminated Sprayer
    • Contaminated Water Supply
    • Contaminated Fertilizer or Spreader Equipment
      Triazines

   Chemicals
    • Atrazine
    • Simazine
   Symptoms
    • Dead tissue between
      secondary veins
    • Green or yellow
      tissue adjacent to
      vein
Triazine Test                Crop Exposure

   < 0.05 ppm No               Run-off
    damage                      Contaminated
   0.05 - 0.20 Injury           Sprayer
    possible depending           • Corn Sprayer
    on climatic conditions       • Back Siphon
   > 0.20 Injury               Contaminated
    expected                     Fertilizer Buggy
                                 • Use of same buggies
                                   used for corn
               Growth Regulators

   2,4-D, etc.
    • Damage only to developing leaves at time of drift
    • Can assess date of exposure
   Banvel
    • Similar to 2,4-D
          But damage more persistent
   Tordon
    • Extreme sensitivity in tobacco .3 ppb
    • Water Soluble
    • Persistent in soil
Growth Regulator Symptoms
                 Accent/Beacon

   Form Johnsongrass control in corn
   Drifts for a considerable distance
   Yellowing
    • Leaf tip
    • Spots
   Causes restricted Vein (stem) growth
    • Lamina puckers
Accent/Beacon - Symptoms
Callisto
Unknown
Sheep Dip
 Skunk
Damage

								
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