The effects of temperature and humidity on the off-host survival of Psoroptes ovis and Psoroptes cuniculi

The effects of both temperature and humidity on the survival of the mites P soroptes ovis and Psoroptes cuniculi were considered in laboratory assays. When P. ovis and P. cuniculi were maintained at 95% humidity, maximum survi val decreased linearly with increasing temperature, from approximately 15 d ays at 9 degrees C to 5 days at 30 degrees C. There was no significant diff erence between P. ovis and P. cuniculi in the effects of temperature on max imum survival. Adult male P. ovis and P. cuniculi had lower mean maximum su rvival than any of the other life cycle stages. There was a small but signi ficant effect of humidity on survival for P. cuniculi; LT50 values were gre ater at 75-85% r.h. than at 55-65% r.h. The influence of off-host survival and the infestation of naive sheep from mites in the environment on the epi demiology of sheep scab are discussed. (C)1999 Elsevier Science B.V. All ri ghts reserved.