|Dowler, C - USDA ARS - RETIRED|
|Csinos, A - UNIVERSITY OF GEORGIA|
|Sumner, D - UNIVERSITY OF GEORGIA|
Submitted to: Proceedings of Southern Weed Science Society
Publication Type: Abstract Only
Publication Acceptance Date: November 17, 1999
Publication Date: January 26, 2000
Citation: Webster, T.M., Johnson, W.C., Dowler, C.C., Csinos, A.S., Johnson, A.W., Sumner, D.R. 2001. Vegetable weed management using alternatives to methyl bromide [abstract]. Proceedings of Southern Weed Science Society. 53:61. Technical Abstract: Approximately 67% of methyl bromide is used globally for preplant soil fumigation, which must cease by the year 2005. Methyl bromide alternatives must address multiple pests. Field studies were conducted in 1998 and 1999 to evaluate various fumigant treatments on control of soilborne diseases, nematodes, and weeds. Studies included: a three-crop rotation (within each hyear) of squash-cucumber-squash and a second study, two crop per season rotation of bell pepper-squash. Treatments to the first crop in both rotations included methyl bromide (392 lbs ai/A), chisel injected 1,3-dichloropropene (1,3-D) (19 gal/A), drip tape application of 1,3-D (19 gal/A), and a nontreated control (NTC). The squash-cucumber- squash test also included a combintation of 1,3-D (12 gal/A) + chloropicrin (6.6 gal/A) + metham (50 gal/A) in 1999. The pepper-squash test had a drip tape application of methyl iodide (392 lbs ai/A). The second and third crops received applications through the drip tape of metham, 1,3-D, or were nontreated. Purple nutsedge populations were 74-100% lower in the methyl bromide plots relative to the NTC. The combination of 1,3-D + chloropicrin + metham and the methyl iodide treatments suppressed purple nutsedge numbers early in the season 76 and 91%, respectively. However, both treatments had nutsedg numbers similar to the NTC at the end of the seqson. Chisel-injected 1,3-D reduced purple nutsedge levels greater than 90% in 1998 in the first crop of both the squash and pepper rotations. However, the level of weed control in 1999 from this treatment was not different than the NTC. While some options will provide purple nutsedge suppression, the search for a methyl bromide alternative for nutsedge control continues.