Submitted to: Proceedings of Methyl Bromide Alternatives Conference
Publication Type: Proceedings
Publication Acceptance Date: 11/30/2009
Publication Date: 11/30/2009
Citation: Walters, T., Patrika, M., Zasada, I.A., Pinkerton, J.M. 2009. Methyl bromide alternatives for raspberry nurseries. Proceedings of Methyl Bromide Alternatives Conference. 26-1 - 26-4. Interpretive Summary:
Technical Abstract: Raspberry nurseries must produce plants free from disease to meet marketplace and export requirements. Minor disease infestations in nurseries can cause severe epidemics in production fields. Raspberry nurseries presently qualify for critical use and quarantine/preshipment exemptions to use Methyl Bromide (MB), but there is increasing pressure to find alternatives. Root rot caused by Phytophthora rubi (PR) and the root lesion nematode Pratylenchus penetrans (PP) are the most serious root diseases of red raspberries in many growing regions. Crown gall (Agrobacterium tumefasciens, AT) is common in the coarse-textured soils favorable to raspberry nursery production. Soil fumigation with MB reduces but does not consistently eliminate crown gall. Improved AT control would be a very attractive feature of a MB alternative for raspberry nurseries. Methyl bromide is also valued by raspberry nurseries for its role in eliminating other pathogens and weeds. Our objective was to evaluate alternatives to MB:chloripicrin fumigation for reduction of pathogens and weeds in raspberry nursery production. In field evaluations, methyl bromide:chloropicrin and Midas (iodomethane) were the most effective treatments overall, but the expense of Midas is a barrier to adoption. Soil solarization plus Inline reduced AT better than methyl bromide:chloropicrin, however, this treatment failed to provide adequate control of PR, and is probably not appropriate for nursery production. Bed fumigation, although atypical for raspberry nursery production, has potential for effective soil fumigation. Less fumigant is required, which reduces expense, emissions and buffer zone size. In addition, raspberry cut roots were planted earlier in bed fumigated plots compared to flat-fumigated plots.