Weed control with methyl bromide alternatives.

Abstract

Abstract Methyl bromide (MeBr) has been used for several decades for preplant (PRE) 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 an 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.