Weed Control Competition • • • • Space Light Nutrient Water Physical Damage • Morningglories • Honeyvine Milkweed Weeds Tolerance to Competition Weed free for 6 weeks • Tobacco canopy tolerates late competition Weedy for 4 weeks • Weed Control.
Download ReportTranscript Weed Control Competition • • • • Space Light Nutrient Water Physical Damage • Morningglories • Honeyvine Milkweed Weeds Tolerance to Competition Weed free for 6 weeks • Tobacco canopy tolerates late competition Weedy for 4 weeks • Weed Control.
Weed Control Competition • • • • Space Light Nutrient Water Physical Damage • Morningglories • Honeyvine Milkweed Weeds Tolerance to Competition Weed free for 6 weeks • Tobacco canopy tolerates late competition Weedy for 4 weeks • Weed Control after weedy problem No competition 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 Cultivation Shallow Cultivation • Scrapes surface • Hills plants • Faster Speed Rolling Cultivators 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 Annual grasses Many Broadleaf weeds • Pigweed • Poor Control Rhizome Johnson Grass Hairy Galinsoga Common Ragweed 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 Stunting Mitotic poison Not taken up by plants Activity & Mode of Action Symptoms Symptoms Symptoms – Phosphorus Deficiency Persistence Can cause cover crop damage especially in dry seasons Weed Spectrum • Good Control Annual Grasses Most Broadleaf Weeds including • Common Ragweed • Hairy Galinsoga • Velvetleaf Command 3 ME 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 Application Placement • Best not incorporated Due to crop safety OK to scratch out tractor track Photosensitizes Plants actively take-up • Exposure to sunlight causes membrane disruption • Susceptible plants turn necrotic and die Activity & Mode of Action 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 • Fair to Poor Control Many Broadleaf Weeds • Crop Safety Good Damage possible under specific conditions Tillam 6E 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 % Control 100 80 60 40 20 0 Prowl + Spartan 4F Command + Spartan 4F Weedy Check LSD Prowl Command Spartan 4F Annual Grass 75 86.25 88.75 95 97.25 0 15.4 Pigweed 85 15 95 97.25 88.75 0 23.8 82.5 87.5 97.5 95 98.75 0 8.6 96.25 100 87.5 91.25 100 0 10 87.5 57.5 92.5 95 98.75 25 37.2 0 5 37.5 0 22.5 0 34.8 Yellow Nutsedge Common Ragweed Morningglories Carpetweed 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 Poast 1.53E 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 < 0.05 ppm No damage 0.05 - 0.20 Injury possible depending on climatic conditions > 0.20 Injury expected Crop Exposure Run-off Contaminated Sprayer • Corn Sprayer • Back Siphon Contaminated 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