Submitted to: International Conference on Methyl Bromide Alternatives and Emissions Reductions
Publication Type: Abstract only
Publication Acceptance Date: 9/15/2007
Publication Date: 10/29/2007
Citation: Johnson, J.A. 2007. Effect of product moisture on efficacy of vacuum treatments for tree nuts. International Conference on Methyl Bromide Alternatives and Emissions Reductions. 83.1-4. Interpretive Summary:
Technical Abstract: California tree nuts (walnuts, almonds and pistachios) must be free of insect infestation in order to meet consumer demands and export requirements. Processors have long relied on fumigants such as methyl bromide to disinfest their product of field pests such as codling moth (Cydia pomonella) and navel orangeworm (Amyelois transitella), as well as storage pests such as Indianmeal moth (Plodia interpunctella). Recently, the development of flexible, inexpensive, portable containers has made possible the use of vacuum treatments as a non-chemical alternative. Because the mechanism of vacuum treatments is partially dependent on the drying effect of low atmospheric pressures, product moisture may have an effect on treatment efficacy. This study demonstrated that high humidities due to high product moisture levels reduces moisture loss of test insects and improves their survival during vacuum treatments. Diapausing larvae were more resistant to moisture loss, and more tolerant of vacuum treatments. Vacuum treatments are more suitable for applications such as smaller producers and organic processors, and identifying the potential of product moisture to affect efficacy should improve the success of this alternative treatment and speed its adoption.