1Department of Plant Protection, Faculty of Plant Production, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran.
2Department of Agricultural Entomology, Plant Protection Research Institute, Tehran, Iran.
3Biological Control Research Laboratory, Plant Protection Research Institute, Amol, Iran.
4Department 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 24 ± 2 ºC, 80 ± 5% relative humidity and a photoperiod of 16:8 (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 220.85 ± 5.78 and 119.44 ± 2.1 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 (R0) were significantly higher on Ps. viburni than on Pl. citri.The values of intrinsic rate of increase were estimated 0.081and 0.094 day-1 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.