Gholam Ali Abdollahi Ahi - Department of Plant Protection, Faculty of Plant Production, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran.
Ali Afshari - Department of Plant Protection, Faculty of Plant Production, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran.
Valiollah Baniameri - Department of Agricultural Entomology, Plant Protection Research Institute, Tehran, Iran.
Hemmat Dadpour - Biological Control Research Laboratory, Plant Protection Research Institute, Amol, Iran.
Mohsen Yazdanian - Department of Plant Protection, Faculty of Plant Production, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran.
Ali Golizadeh - Department of Plant Protection, Faculty of Agriculture, University of Mohaghegh Ardabili, Ardabil, Iran.

Biological and demographic parameters of the mealybug ladybird, Cryptolaemus montrouzieri (Mulsant) were evaluated on citrus mealybug, Planococcus citri (Risso) and obscure mealybug, Pseudococcus viburni (Signoret) under ۲۴ ± ۲ ºC, ۸۰ ± ۵% relative humidity and a photoperiod of ۱۶:۸ (L: D) h. The mealybugs had a significant effect on developmental time and reproductive and demographic parameters of the ladybird. Life span (egg to adult death) was obtained ۲۲۰.۸۵ ± ۵.۷۸ and ۱۱۹.۴۴ ± ۲.۱ days when fed on Pl. citri and Ps. viburni, respectively. However, mean number of eggs per female (fecundity) and mean percent of egg hatching were significantly higher on Ps. viburni than on Pl. citri. In addition, values of intrinsic rate of increase (rm), finite rate of increase (λ) andnet reproductive rate (R۰) were significantly higher on Ps. viburni than on Pl. citri.The values of intrinsic rate of increase were estimated ۰.۰۸۱and ۰.۰۹۴ day-۱ on Pl. citri and Ps. viburni, respectively. Results of this study suggested that the obscure mealybug is a more suitable prey than the citrus mealybug as the ladybird displayed shorter developmental time, and higher fecundity and growth rate when fed with obscure mealybug.

Life table, Mealybug ladybird, Pseudococcidae