Efficacy of extreme temperatures and the combination of heat with the fumigant sulfuryl fluoride to control the mold mite

Tyrophagus putrescentiae(Schrank), known as the ham mite, mold mite or cheese mite, is a widely distributed pest species infesting grains and stored food products with high fat and protein contents. Methyl bromide has been used in country ham plants to control this pest for decades. However, methyl bromide is classified as an ozone depleting substance and will be phased out for all industries by the end of 2015. Therefore, there is a significant need to find a feasible and effective alternative to prevent and control mite infestations. This study has evaluated the efficacy of extreme temperatures alone and application of heat in combination with sulfuryl fluoride (SF) on mortality of mold mite. Ten eggs and a mixture of forty adults/nymphs were separately exposed to different high and low temperatures, ranging from +35 to 45°C and from -10 to +5°C, for several periods of time. Furthermore, fumigated vials with mite eggs or a mixture of mobile stages were kept at high temperatures for two days. Mortality was assessed after a recovery period for each life stage. Results showed that complete egg mortality occurred after 24 hrs. at 45°C, while 100% of mobile stages after 3 hrs at that temeprature. At low tested temperatures, all life stages of mites died after 18 hrs. at -10°C. Combination of SF and heat indicated that after 48 hrs. exposure time, 100% mortality happened at 35°C in mobile stages, however total egg mortality occurred at 40°C with the same amount of SF.