Submitted to: Methyl Bromide Alternatives and Emissions Research Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: October 1, 2009
Publication Date: November 13, 2009
Citation: Walse, S.S., Tebbets, J.S., Leesch, J.G. 2009. Ovicidal Efficacy of Sulfuryl Fluoride to Stored-Product Pests of Dried Fruit. Methyl Bromide Alternatives and Emissions Research Conference Proceedings, November 10-13, 2009, San Diego, CA. p. 60.1-2 Technical Abstract: Chemical fumigants are an important component of protecting postharvest commodity from insect pests. Sulfuryl fluoride, originally produced and marketed as the structural fumigant Vikane®, has transitioned toward use in durable commodities as ProFume®. Substantial laboratory- and commercial-scale data exists on its efficacy in controlling insect infestation in grain and flour mills; its deficiency as an ovicide, relative to methyl bromide, has been observed in many of these studies. Almost no empirical data has been generated with respect to its efficacy for controlling insect infestations pertinent to stored dried fruit, such as figs, raisins, and prunes. This work details sulfuryl fluoride treatment schedules over 60-80 C, at both atmospheric pressure (760 mmHg) and reduced pressure (100 mmHg), for the control of Plodia interpunctella (indianmeal moth, IMM), Tribolium castaneum (red flour beetle, RFB), and Carpophilus hemipterus (dried fruit beetle, DFB) egg stages. Initial dose-mortality investigations confirmed the egg stage as the most tolerant life stage of IMM, RFB, and DFB. The statistical regression of data shows that the transition from nonlethal to lethal doses occurs over a range of greater than an order of magnitude for RFB, approximately equal to an order of magnitude for IMM, and less than an order of magnitude for DFB. The relationship between the sulfuryl fluoride dose required to elicit mortality and the inflection of that mortality is curious and warrants future investigation, particularly with respect to the “tolerant” yet “reactive” response of DFB eggs relative to the other species tested. This data will be used directly by the California dried fruit industry, the Environmental Protection Agency, and the Methyl Bromide Technical Options Committee as they work in concert to develop agriculturally, economically, and environmentally sound chemical fumigants to replace methyl bromide. Specifically, this work serves as the most comprehensive tool to date for indexing the potential utility of sulfuryl fluoride fumigations, relative to established methyl bromide protocols, for controlling insect pest infestations of stored dried fruit.