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Weed Control. Weeds. Competition Space Light Nutrient Water Physical Damage Morningglories Honeyvine Milkweed. Weed free for 6 weeks Tobacco canopy tolerates late competition. Weedy for 4 weeks Weed Control after weedy problem No competition. Tolerance to Competition. Cultivation.
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Weeds • Competition • Space • Light • Nutrient • Water • Physical Damage • Morningglories • Honeyvine Milkweed
Weed free for 6 weeks Tobacco canopy tolerates late competition Weedy for 4 weeks Weed Control after weedy problem No competition Tolerance to Competition
Cultivation • Shallow (1 inch deep) • Reduces root damage • Doesn’t disturb herbicide placement • Shears of weeds • Breaking crust
Cultivation • Deep Cultivation • Damages roots • Brings up untreated soil • Misconception? • Brings up moisture during a drought
Rolling Cultivators • Shallow Cultivation • Scrapes surface • Hills plants • 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
Good Control Annual grasses Many Broadleaf weeds Pigweed Poor Control Rhizome Johnson Grass Hairy Galinsoga Common Ragweed Cocklebur Suppression Morningglories Prowl 3.3ECWeed Spectrum
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
Activity & Mode of Action • Root & shoot inhibitor • Symptoms • Root pruning • Stunting • Mitotic poison • Not taken up by plants
Persistence Can cause cover crop damage especially in dry seasons
Command 3 ME • Weed Spectrum • Good Control • 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 (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 Application
Activity & Mode of Action • Photosensitizes • Plants actively take-up • 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
Tillam 6E • Weed Spectrum • Good Control • Annual grasses • Nutsedge • 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 TobaccoFayette Co. – David Tucker Farm
Poast 1.53E • Weed Spectrum • Good Control • Annual & perennial grasses • No Control • Broadleaf Weeds • 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
< 0.05 ppm No damage 0.05 - 0.20 Injury possible depending on climatic conditions > 0.20 Injury expected Run-off Contaminated Sprayer Corn Sprayer Back Siphon Contaminated Fertilizer Buggy Use of same buggies used for corn Triazine Test Crop Exposure
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
Accent/Beacon • Form Johnsongrass control in corn • Drifts for a considerable distance • Yellowing • Leaf tip • Spots • Causes restricted Vein (stem) growth • Lamina puckers