WEED CONTROL IN THE LIFE AFTER METHYL BROMIDE

Authors: Johnson, Wiley - Carroll; Webster, Theodore

Submitted to: Southeast Farm Press
Publication Type: Trade Journal
Publication Acceptance Date: 12/30/2002
Publication Date: 12/30/2002
Citation: Johnson, W.C., Webster, T.M. 2002. Weed control in the life after methyl bromide. Southeast Farm Press. 29(27) p.15 and 29(28) p.10-14.

Interpretive Summary: Interpretive summary not required.

Technical Abstract: Vegetable growers are losing the soil fumigant methyl bromide. Efforts are on-going to extend the deadline for using methyl bromide until suitable alternatives are developed. Regardless of whether the deadline is extended or not, growers need to begin to study alternatives to methyl bromide and begin trial implementation into their production systems. In preliminary trials, metham-sodium applied as a spray and incorporated was found to be among the most effective fumigants for controlling yellow nutsedge. Other field trials were conducted in sites with high densities of yellow nutsedge, often greater than 10 plants/ft2, and yellow nutsedge control ranged from 70 to 91%. It was found that successful control of yellow nutsedge with metham-sodium is dependent on irrigating the soil to field capacity one day prior to application, evenly incorporating metham-sodium in zone where nutsedge tubers occur using specialized application equipment, and using a plastic layer that does not aggressively move nontreated soil into the seedbed. Another weed control alternative for methyl bromide is halosulfuron. Halosulfuron controls yellow and purple nutsedge, does not have the extremely long soil-residual problems that plague other related herbicides, and kills nutsedge tubers. Integrated weed management is the long-term solution to weed control without methyl bromide. One component of integrated weed management is using accurate data regarding pest incidence to prevent over-treatment where pests are not present. Another component of integrated weed management involves an understanding of perennial nutsedge ecology that shows weaknesses in the weed life cycle that can be exploited to growers' advantage and where cropping systems are vulnerable to perennial nutsedge infestation. Methyl bromide cancellation appears to be imminent. Growers of vegetable crops need to begin trial implementation of proven alternatives and practice integrated weed management.