Seyedeh Masoumeh Fotukkiaii - Department of Plant Protection, College of Agriculture, University of Guilan, Rasht, Iran
Ahad Sahragard - Department of Plant Protection, College of Agriculture, University of Guilan, Rasht, Iran
Mohammad Fazel Halajisani - Iranian Citrus Research Center, Ramsar, Mazandaran Province, Iran.

Demographic parameters of the ladybeetle, Serangium montazerii Fursch feeding on citrus whitefly, Dialeurodes citri Ashmead were determined on two host plants, Page tangerine and Thompson navel orange. This study was carried out under laboratory conditions (۲۵ ± ۱ °C and RH of ۶۰ ± ۵% and a photoperiod of ۱۶: ۸ h (L: D). Total pre-adult periods of the lady beetle were ۲۰.۸۴ ± ۰.۳۰۲, ۱۹.۲۷ ± ۰.۲۵۱days on Page tangerine and Thompson navel orange, respectively. The survivorship from egg to adult were very close to each other on the two host plants. The oviposition periods were ۲۹.۶۴ ± ۰.۹۰۵ and ۳۳.۳۶ ± ۰.۵۹۹ days and the total number of eggs per female (fecundity) were ۴۵۷.۱۴ ± ۱۱.۰۹۹ and ۵۲۸.۵۷ ± ۱۲.۳۶۹ on Page tangerine and Thompson orange, respectively. Peaks of reproductive value occurred at ages of ۳۱ and ۳۳ days when reared on Thompson navel orange and Page tangerine, respectively. The intrinsic rates of increase (r) on Thompson orange and on Page tangerine were ۰.۱۳۴ ± ۰.۰۶۳ and ۰.۱۲۶ ± ۰.۰۰۶d-۱ with no significant differences. The mean generation time (T) on these host plants were ۳۹.۰۳ ± ۰.۵ and ۴۰.۵۷ ± ۰.۴۶ days, respectively. It can be concluded that S. montazerii feeding on D. citri in general showed a slightly better reproductive performance on Thompson navel orange than on Page tangerine.

Generation time, Intrinsic rate of increase, Life table parameter, S. montazerii, survivorship