The effect of relative humidity on acaricide efficacy against and dispersal characteristics of the mold mite Tyrophagus putrescentiae

Abstract

This study determined the effects of relative humidity on mold mites (<italic>Tyrophagus putrescentiae</italic>) with regard to acaricide efficacy and dispersal characteristics. The mold mite is a stored product pest that can infest retail habitats. Mold mite survival depends on relative humidity (RH), and RH levels may affect efficacy of residual acaricides. In a simulated retail habitat, increasing humidity levels generally decreased acaricide efficacy. Results indicated that some acaricides may create a barrier against this mite. A second study analyzed mold mite dispersal characteristics. Mite infestations may remain undetected until mites leave the food package. Arenas provided an enclosed food reservoir incubated at high RH, and an open space incubated at one of three RH levels. Mite activity was monitored daily until dispersal characteristics were determined. Explosive dispersal, a mass-migration within 24 h, was observed. Therefore, direct sampling of habitat may be necessary to detect infestations before explosive dispersal has occurred.