Alternatives to Methyl bromide in Strawberry Production in the United States of America and the Mediterranean Region

Methyl bromide (MB) is a broad-spectrum soil fumigant, which has been critical in strawberry production for forty years. Strawberry and other high-value cash crops benefit from pre-plant soil fumigation with MB and chloropicrin (Pic). Mixtures of these two fumigants work synergistically in controlling a wide range of plant pathogens and pests, including fungi, nematodes, insects, mites, rodents, weeds, and some bacteria. Methyl bromide was listed in 1993 by the Parties of the Montreal Protocol as an ozone-depleting compound. According to the Montreal Protocol, the import and manufacture of MB in the United States of America (USA) and other developed countries will be banned by 2005, after stepwise reductions in 1999, 2001, and 2003. Currently, there is no single registered alternative fumigant for all of the MB uses and there is a need for environmentally sound and economically feasible alternatives. The fumigants 1,3-dichloropropene (1,3-D) and Pic in combination with methyl isothiocyanate (MITC) generators have shown to be the most promising alternatives to methyl bromide for strawberry production. Studies with the experimental fumigants methyl iodide and propargyl bromide suggested that these compounds have higher reactivity than MB as stand-alone fumigants. This review evaluates the commercially available and experimental alternatives to MB soil fumigation for strawberry production based on relevant scientific publications, proceedings, and personal communications.