Location: Water Management ResearchTitle: Challenges in Weed Management Without Methyl Bromide Author
Submitted to: American Society of Agronomy Meetings
Publication Type: Proceedings
Publication Acceptance Date: 12/15/2008
Publication Date: 2/4/2009
Citation: Hanson, B.D. A. Shrestha. California Plant and Soil Conference Procedings. 2009: 45-48 Interpretive Summary: Methyl bromide has been used as a pre-plant soil fumigant to control a wide range of pests in high value agricultural and horticultural crops around the world. However, use of methyl bromide is being phased out due to damaging effects on stratospheric ozone. Research has been conducted to develop effective alternatives to methyl bromide for control of insects, nematodes, pathogens, and weeds. As alternative approaches are being developed to manage nematode and disease pests, weeds are becoming an even larger concern for growers of high value crops. In this presentation, we discuss both general and specific challenges related to weed control in cropping systems that currently depend on preplant fumigation with methyl bromide. It is concluded that no currently available alternative chemical or management practice has the same broad-spectrum efficacy and consistency as methyl bromide and that an integrated approach to weed management will be necessary to maintain productivity at levels and prices that meet current grower and consumer expectations.
Technical Abstract: Methyl bromide has been used for several decades for pre-plant soil fumigation in high value agricultural and horticultural crops because it can provide broad-spectrum control of insects, nematodes, pathogens, and weeds. However, MeBr has been identified as a powerful ozone-depleting chemical and is associated with hazards to human heath, plants, and animals. Therefore, a global agreement to gradually phase-out ozone depleting chemicals was made with the signing of the ‘Montreal Protocol’ in 1987 and research for effective and sustainable alternatives to MeBr has been a priority since 1995. Several alternative fumigants and non-chemical alternatives for weed control have been tested. In many agricultural systems the phase-out of MeBr presents a critical challenge because alternative pest control measures are ineffective, costly, or pose hazards to the environment and human health. In this paper we review the status of MeBr alternatives with a focus on weed control in high value cropping systems. It is concluded that no currently available alternative chemical or management practice has the same broad-spectrum efficacy and consistency as MeBr. Because the development of a single alternative to MeBr is unlikely, weed control in many high value fruit, vegetable, and ornamental crops will become an even greater challenge in the absence of MeBr. Development of crop and region specific integrated pest management systems that include appropriate fumigants, herbicides, and cultural practices will be necessary to maintain productivity at levels and prices that meet current grower and consumer expectations.