Abstract: The present paper deals with egg diapause of Oligonychus ununguis(Jacobi). The effects of factors influencing diapause incidence including light, temperature and nutrition were investigated, and the condition terminating diapausewas recorded. O. ununguis overwinters with diapause eggs on host plant branches.Most eggs are laid in the beginning and middle of August. The threshold of photoperiod inducing diapause is at 13 hours light per day. The larva, protonymph are sensitive to photoperiodic changes, but adults and eggs are not. Lower temperature (20℃) promotes the incidence of diapause, when they are subject under the photoperiod of 10 or 13 hours per day. Similarly, diapause is also promoted by mite population density and unfavourable nutrition. The dlapause was terminated after treatment at 0℃ for 120 clays or at 5℃ or 10℃ for 100 days.

Key words: Oligonychus ununguis, diapause