No abstract

Seasonal changes in reproductive state were investigated in the pear psylla Cacopsylla bidens (Šulc), with a particular emphasis on the evaluation of reproductive diapause during autumn and winter. Changes in reproductive status were observed in both seasons in populations living at four altitudes: 70, 300, 700 and 730 m. Winterform psylla females exhibited a period of slow ovarian development and a low mating rate. The onset, duration and extent of this period varied among the four sites but terminated synchronously, around December 20th. These changes were consistent within the same population over 3 years. Laboratory and field data suggested that winterform female C. bidens maintain some characteristics of reproductive diapause. By manipulating photoperiod and temperature during psylla development, we showed a major role for photoperiod in the induction of a reproductive diapause‐like state. However, as observed under natural conditions, the timing of the decrease in ovarian development and mating was highly dependent on the decrease in temperature. The fact that the initiation of reproductive activity was synchronous and highly predictable is very significant for the design of phenologically based management for this pest.