Diapause induction and termination in the predatory mite Euseius finlandicus in peach orchards in northern Greece.

The course of diapause induction as well as of diapause termination in females of the predatory mite Euseius (Amblyseius) finlandicus Oudemans (Acari: Phytoseiidae) in Northern Greece was determined by transferring females during winter and early spring from peach trees to a short day (LD 8:16) or a long day (LD 16:8) photoperiod both at 20 degrees C. The first diapause females were found in mid September and by the first week of October all the females were in diapause. The mean number of days required for diapause termination under the short day photoperiod LD 8:16 was gradually reduced from 93.7 days in the beginning of October to less than 20 days in mid February and early March. Under the long day photoperiod of LD 16:8 diapause was terminated in less than 20 days irrespective of the date of collection. These results indicate that by mid February photoperiodic sensitivity of females was lost and diapause was terminated. However, females were found in their overwintering sites until the second half of March, probably because of the prevailing relatively low temperatures and lack of adequate food.