Vikane gas in the treatment of potentially infested collections materials

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Sulfuryl fluoride is highly toxic to all post-embryonic life stages of insects (UNEP 1994), eggs of most species are less susceptible (DowElanco 1996a; Bond 1984). The efficacy of sulfuryl fluoride depends on the concentration reaching the target pest and the duration of exposure. As a result, the dosage of sulfuryl fluoride required for a specific pest is calculated in "ounce-hours," ounces of Vikane™ multiplied by hours of exposure. In general, insect eggs require a higher ounce-hour dosage of sulfuryl fluoride compared to later life stages (i.e., a 10-fold increase in dosage for some insect species) (UNEP 1992, UNEP 1994). However, the ability to control egg stages of social insects (i.e., termites and ants) is not necessary because these newly hatched larvae cannot survive without adult care. Furthermore, the higher dosages required to control insect eggs can be obtained by increasing the exposure time, concentration of sulfuryl fluoride, or a combination of the two. Fumigators use a "fumiguide calculation system" to determine the amount of Vikane™ required for specific pest and fumigation conditions (DowElanco 1994 and 1996a).
Sulfuryl fluoride prevents insects from metabolizing the stored fats they need to maintain a sufficient source of energy for survival by disrupting the glycolysis cycle (Meikle et al. 1963). Mortality may be delayed for insects for several days following fumigation (Osbrink et al. 1987), therefore insects that have received a lethal exposure to sulfuryl fluoride may still be alive immediately following fumigation (no longer than 3 to 5 days for termites) (DowElanco 1994). Sulfuryl fluoride has also been demonstrated to reduce oxygen uptake in insect eggs (Outram 1970).