DEMOGRAPHIC-STUDY OF THE REPRODUCTIVE POTENTIAL OF PEAR PSYLLA, CACOPSYLLA-PYRI

Longevity and fecundity of pear psylla adults, Cacopsylla pyri (L.) (H omoptera: Psyllidae), were studied in Greece under field conditions, d uring 1991/92 and 1992/93. Net fecundity (mean fecundity of cohort) of the overwintered females (winter form) was low (24.1 and 43.4 eggs pe r female for 1991/92 and 1992/93 respectively) because only a small fr action of the females survive reproductive diapause. Surviving females , however, are capable of producing a relatively high number of-eggs ( 135.0 and 151 9 eggs per female for the two seasons respectively). Net fecundity of summer form females was very high in spring (343.2 and 4 06.8 eggs per female for 1992 and 1993 respectively), relatively high in early autumn (130.4 and 192.5 eggs per female) and very low in summ er (21.9 and 46.5 eggs per female). Male longevity was in all cases sh orter than that of female. Longevity of both sexes of the summer form was higher in spring and autumn (for females it ranged from 22.3 to 28 .4 days) than it was in summer (for females it ranged from 14.3 to 17. 4 days).