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2008 Methyl Bromide Alternatives Conference: DMDS or the 3-WAY: Which is More Effective in GA. University of Georgia Tifton Campus Culpepper, Webster, Rucker, Sumner, Beard, Langston, Mayfield. 2007 Large Acreage On-Farm Trials. Fumigant and mulch options: 3-WAY under LDPE
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2008 Methyl Bromide Alternatives Conference: DMDS or the 3-WAY: Which is More Effective in GA University of Georgia Tifton Campus Culpepper, Webster, Rucker, Sumner, Beard, Langston, Mayfield
Fumigant and mulch options: • 3-WAY under LDPE • MIDAS under Blockade • DMDS under LDPE • MB under Blockade 2007 On-Farm Comparisons
Boxes of Bell Pepper for Total Harvest. Data presented as % of MB. 2007.* *Data totaled over three harvests. MB fruit: Jumbo (14%), X-Large (32%), Large (27%), and Chopper (26%).
2008 Objectives • Confirm the most effective mixture of DMDS and chloropicrin was a 79:21 when applied under high barrier mulch. • Define the rate needed under high barrier mulch. • Compare the most effective DMDS system to the standard in a large acreage on farm trial. • Focus on annual grasses and pigweeds.
Treatments • Factorial treatment arrangement (3 reps): Formulations (DMDS/Pic) Rates 79:21 30 Gal/A 90:10 40 Gal/A 100:0 50 Gal/A 60 Gal/A • Blockade Mulch
Treatments • Additional treatments: 1. 3-WAY (12/150/75) LDPE mulch 2. DMDS 79:21 60 Gal LDPE mulch 3. Non-treated control Blockade mulch
Materials and Methods • Applications were made on Feb 17 • Soil temperatures were 60 F at injection • Soil moisture was 95% of field capacity. • Sandy loam soil type • Plot size 1 bed (2 rows of pepper) by 50 ft
Materials and Methods • Yellow nutsedge and large crabgrass • Plant growth • Nematodes • Yield (4 harvests of Jumbo fruit)
Percent yellow nutsedge control at harvest as impacted by DMDS formulation and rate. TyTy, GA 2008.* 100 a 100 a 99 a 98 a 98 a 100 a 97 b 60 G 79:21 30 G 50 G 40 G 90:10 100:0 Rate Main Effect Formulation Main Effect *Values within main effect followed by the same letter are not different at P = 0.05
Percent large crabgrass control at harvest as impacted by DMDS formulation and rate. TyTy, GA 2008.* 75 a 69 a 66 b 55 b 49 c 42 c 33 d 60 G 79:21 30 G 50 G 40 G 90:10 100:0 Rate Main Effect Formulation Main Effect *Values within main effect followed by the same letter are not different at P = 0.05
Percent large crabgrass control 55 d after fumigating as impacted by DMDS formulation and rate. TyTy, GA 2008.* 99 a 98 a 98 a 98 a 94 b 97 a 96 a 60 G 79:21 30 G 50 G 40 G 90:10 100:0 Rate Main Effect Formulation Main Effect *Values within main effect followed by the same letter are not different at P = 0.05
Plant Heights and Nematodes • Plant heights taken 20 and 50 DAP with no differences. • No nematodes present in the study.
Jumbo fruit number per plot as impacted by DMDS formulation and rate. TyTy, GA 2008.* 210 a 203 194 197 181 b 175 b 162 * 60 G 79:21 30 G 50 G 40 G 90:10 100:0 Rate Main Effect Formulation Main Effect *Values within main effect followed by the same letter are not different at P = 0.05
Percent yellow nutsedge control at harvest as impacted by DMDS formulation and rate. TyTy, GA 2008.* 100 a 100 a 90 b DMDS 79:21 60 G LDPE DMDS 79:21 60 G Bloc 3-WAY LDPE *Values within main effect followed by the same letter are not different at P = 0.05
Percent large crabrass control at harvest as impacted by DMDS formulation and rate. TyTy, GA 2008.* 100 a 89 b 33 c DMDS 79:21 60 G LDPE DMDS 79:21 60 G Bloc 3-WAY LDPE *Values within main effect followed by the same letter are not different at P = 0.05
Jumbo fruit number per plot as impacted by DMDS formulation and rate. TyTy, GA 2008.* 270 a 244 a 66 b DMDS 79:21 60 G LDPE DMDS 79:21 60 G Bloc 3-WAY LDPE *Values within main effect followed by the same letter are not different at P = 0.05
On Farm Trial • Four treatments: • DMDS 79:21 60, 50, 40 G Blockade mulch • 3-WAY 12/150/75 under LDPE • 2. Plots 3 rows by 1200 feet • 3. Four Replications
Measurements taken: • Weeds emerging through mulch or plant hole • Crop height • Pathogens • Nematodes • Pepper Harvest (4 times) • Packing House Grades
Number of Purple Nutsedge, Crabgrass, and Livid Amaranth Plants/A with MB Alternatives in Pepper. LTF, Spring 2008.* *Values within species followed by the same letter are not different at P = 0.05 Nutsedge and amaranth counts are at harvest, crabgrass counts early season followed by two applications of Select during the season.
Plant Height and Nematodes 1. No differences in crop growth 2. No differences in disease or nematodes
48 people picking 5 truck drivers 12 UGA dumpers Once a week for 4 weeks
Harvest 1: 3 hr Harvest 2: 3 hr Harvest 3: 5 hr Harvest 4: 5 hr
Harvest 1: 2 hr Harvest 2: 2 hr Harvest 3: 6 hr Harvest 4: 5 hr
CONCLUSIONS 3-WAY: continues to perform well in the spring and continues to perform poorly on nutsedge in the fall
CONCLUSIONS DMDS: 1. 79:21 formulation is the most effective 2. 45 to 50 G in spring but 50 to 60 gallons in fall, depending on herbicides 3. Excellent nutsedge control; needs help on annual grasses, pigweed, and likely other small seeded annual broadleaf weeds. 4. Smell and cost must be addressed.
ON FARM COOPERATOR Bill Brim, LTF