This study was carried out on cotton mealybug, Phenacoccus solenopsis Tinsley
(Hemiptera: Sternorrhyncha: Coccoidea : Pseudococcidae) in Scale Insects and Mealybugs
Department, Plant Protection Research Institute, Sharkia Branch. It was done during the period
extended from July to November 2018 to study periods of the developmental stages of the tested insect
under laboratory conditions 25 ± 1˚C, 65 ± 5% RH and a photoperiod 12 hrs., for the possible use of
this information in mass rearing and designing prediction and control programs of this pest. Results
showed that three nymphal instars were recorded for females with no pupal stage, while only two
nymphal instars and a pupal stage were recorded for males. The developmental periods for first,
second, third nymphal instars, adult female longevity, life cycle and generation were 6.41, 4.45, 7.09,
28.17, 46.12 and 29.76 days, respectively. The developmental periods for first, second, pupal stage
and adult male longevity were 7.10, 8.49, 9.05 and 2.0 days, consecutively. The females showed
dynamic patterns of fecundity with the number of crawlers produced per female ranging between 120
and 385, with a mean of 227.