Retrospective evaluation of costs associated with methyl bromide critical use exemptions for open field strawberries in California

Methyl bromide (MBr) has been widely used as a fumigant to control pests in the agricultural sector, but it is also an ozone depleting substance. After 2005, methyl bromide could only be produced when a critical use exemption was agreed to by the signatories to the Montreal Protocol. This paper examines how the EPA’sex antecost analyses for open field fresh strawberries in California for the 2006–2010 seasons compare to anex postassessment of costs. A key input into theex antecost analysis is the assumed yield loss associated with methyl bromide alternatives. The EPA used conservative assumptions given the wide range of estimates in the literature at the time, but it appears that a number of viable MBr alternatives – either new fumigants or new ways of applying existing fumigants – may have become available more quickly and resulted in lower yield loss than initially anticipated. Likewise, it appears that farmers who substituted away from methyl bromide did so without imposing large negative impacts on production in prime California strawberry growing areas.Ex postevaluation also confirms the effect of California regulatory restrictions in limiting the use of various economically competitive alternatives. It is worth noting that unanticipated complications after switching away from methyl bromide, such as new diseases, slowed the transition to MBr alternatives.

Methyl Bromide Alternatives for Root-Knot Nematodes Control in Tobacco Transplant Production

Field studies were conducted to evaluate potential methyl bromide alternatives against nematods in tobacco (Nicotiana tabacum L.). Metham-sodium and dazomet were evaluated respectively under a polyethylene cover as alternatives for methyl bromide in tobacco transplant production over a two-year period (2009-2010). One genera or species of nematodes, tobacco root-knot nematod (Meloidogyne spp.), was evaluated in Qingzhou, Shandong province of China. All of the fumigant candidates were successful in controlling the pest. Another Parameter, plant vigor, was measured too. Metham-sodium 60g/m2, dazomet 80g/m2 and methyl bromide were not significantly different (P=0.05) from each other in the parameters evaluated. Results of this study indicate that Metham-sodium and dazomet are potential methyl bromide alternatives available to growers for use in tobacco parasite nematods control.