390 likes | 560 Views
Weed Control Without Methyl Bromide. Drs. Stanley Culpepper and Ted Webster University of Georgia and USDA-ARS Tifton, Georgia. Methyl Bromide Phasing out of the marketplace 1999 = 25% reduction 2001 = 25% reduction 2003 = 20% reduction 2005 = gone
E N D
Weed Control Without Methyl Bromide Drs. Stanley Culpepper and Ted Webster University of Georgia and USDA-ARS Tifton, Georgia
Methyl Bromide • Phasing out of the marketplace 1999 = 25% reduction 2001 = 25% reduction 2003 = 20% reduction 2005 = gone (reduce methyl bromide ai over time)
U.S. Countries Using Methyl Bromide Italy Japan Spain France Mexico Brazil 37% Turkey Belgium Morocco Greece South Africa China Costa Rica
Replacing Methyl Bromide • A multi-tactic approach is needed and should include the following: • application of weed biology • cultural practices • fumigants • herbicides
Yellow Nutsedge: - Yellow florets - All tubers attached to mother tuber - Suppressed by bentazon and metolachlor - Leaves: long drawn-out tip Purple Nutsedge: - Dark red/purple florets - Forms chains of tubers - Not suppressed with bentazon or metolachlor - Leaves: short, abrupt tip
Purple Nutsedge Yellow Nutsedge Objective: Evaluate the Spatial Dynamics of Yellow and Purple Nutsedge Expansion After 3 Months (From a Single Planted Tuber)
Alternatives to Methyl Bromide for Weed Management? • Soil Solarization/Organic Amendments • Requires a hot and cloudless climate • Studies have shown that: • solarization can reduce pests prior to planting • crop yields can be increased • effects can be extended through several seasons • Research has focused on pathogens and nematodes - only a handful of studies on weeds
How hot does the soil temperature get underneath plastic? Is it hot enough to kill nutsedge?
Preliminary ConclusionsLethal Temperature/Duration of Exposure: • Yellow Nutsedge: • 113 F for 8 hours = > 90% Tuber Viability • 122+ F for 15 minutes = < 50% Tuber Viability • Purple Nutsedge: • 122 F for 8 hours = > 70% Tuber Viability • 131 F for 4 hours = < 20% Tuber Viability • 140 F for 1 hour = < 5% Tuber Viability • How hot can we get our soils? • How long can they stay this hot?
Alternatives to Methyl Bromide for Weed Management? • Fumigants: • Chloropicrin • Metam Sodium • Methyl Iodide • Telone, Telone II • Telone C17/C35
Methyl Bromide • chickweed • crabgrass • goosegrass • crowfootgrass • pigweed • morningglory? • purslane • nutgrass
Telone II, Telone C-17/35, Chloropicrin • No mention of specific weeds controlled
Non-treated Telone Broadcast Telone In Bed 25 GPA 35 GPA Photos taken from Florida Field Day. Bill Stall, 2000.
Metam Sodium • chickweed • dandelion • ragweed • lambsquarters • pigweed • nightshades • purslane • nutsedge, morningglory - suppression
Metam Sodium • Nutsedge – 1) May be suppressed if actively growing and a high use rate is applied (75 gal/A). 2) More often roots and shoots will be controlled, but the tuber will remain viable and re-grow at a later time.
METHYL BROMIDE: 400 LBS (98%) NONTREATED CONTROL
Purple Nutsedge Through Plastic in Squash: Shoots/Plot • Methyl Bromide (392 Lbs/A - Fumigated): • 1998: 99% lower than UTC (*) • 1999: 99% lower than UTC (*)
Purple Nutsedge Through Plastic in Squash: Shoots/Plot • Methyl Bromide (392 Lbs/A - Fumigated): • 1998: 99% lower than UTC (*) • 1999: 99% lower than UTC (*) • Telone C-35 EC (12 Gal/A) - Drip: • 1998: 81% lower than UTC (*) • 1999: 40% greater than UTC (NS)
Purple Nutsedge Through Plastic in Squash: Shoots/Plot • Methyl Bromide (392 Lbs/A - Fumigated): • 1998: 99% lower than UTC (*) • 1999: 99% lower than UTC (*) • Telone C-35 EC (12 Gal/A) - Drip: • 1998: 81% lower than UTC (*) • 1999: 40% greater than UTC (NS) • Telone II + Chloropicrin + Vapam (12 Gal/A - Chisel ) and (6.6 + 50 Gal/A - Drip): • 1999 Early Season: 76% lower than UTC (*) • 1999 Late Season: 22% greater than UTC (NS)
13 Days After Treatment Telone II + Chloropicrin + Vapam(12 Gal/A - Chisel ) and (6.6 + 50 Gal/A - Drip) Nontreated Control
Purple Nutsedge Through Plastic: Shoots/Plot • Methyl Iodide (392 Lbs/A - Drip): • 1998: 81% lower than UTC (*) • 1999: 21% greater than UTC (NS)
Alternatives to Methyl Bromide for Weed Management? • Herbicides • Limited # of Registered Compounds • Cucurbits (3-5) - no nutsedge materials • Eggplant (4) - no nutsedge materials • Pepper (5) - no nutsedge materials • Squash (4) - no nutsedge materials • Tomato (7) - Tillam for nutsedge suppression • IR-4 is working to increase this list
Sandea • Gowan • Halosulfuron-methyl • 75% active ingredient • MAY be labeled in FL in 2001 • Ever labeled in GA???? • Rate unknown -- probably 0.024 lb ai/A
Sandea for Vegetable Weed Control 1-3 inch 1-9 inch passionflower cocklebur redroot pigweed ragweed pokeweed velvetleaf yellow nutsedge - suppression purple nutsedge - suppression 2 to 3 weeks residual weed control
Yellow Nutsedge Control with Sandea Applied PRE in Watermelon.* % control *In cooperation with Ken Lewis, Crisp County, 2000. Rating 21 days after treatment.
Yellow Nutsedge Control with Sandea Applied POST in Watermelon.* % control *In cooperation with Ken Lewis, Crisp County, 2000. Rating 21 days after treatment.
Sandea Potential Crops (in order of crop tolerance?) tomato
Number of Tomato Boxes Per Acre After Sandea Treatments. Spring, 2000.* *In cooperation with Joel Hudgins, Decatur County, 2000.
Number of Tomato Boxes Per Acre After Sandea Treatments. Spring, 2000.* *In cooperation with Joel Hudgins, Decatur County, 2000.
Number of Tomato Boxes Per Acre After Sandea Treatments. Fall, 2000.* *In cooperation with Joel Hudgins, Decatur County, 2000.
Sandea Potential Crops (in order of crop tolerance?) tomato cucumber pumpkin cantaloupe watermelon
Nontreated Sandea (0.024 lb ai/A) Watermelon farm in Crisp County, May 2000. Treatment at 1-leaf.
Watermelon Injury with Sandea Applied PRE in Watermelon.* % injury *In cooperation with Ken Lewis, Crisp County, 2000. Rating 21 days after treatment.
Watermelon Injury with Sandea Applied POST to 3-inch Watermelon.* % injury *In cooperation with Ken Lewis, Crisp County, 2000. Rating 5 days after treatment.
Watermelon Injury with Sandea Applied POST to 14-inch Watermelon.* % injury *In cooperation with Ken Lewis, Crisp County, 2000. Rating 5 days after treatment.