Effects of Constant Photoperiods and Temperatures on the Hibernating Life Stages of the San Jose Scale (Homoptera: Diaspididae) in North Carolina

The black cap phase of the first instar nymph accounted for about 85% of the hibernating life stages of San Jose scale, Quadraspidiotus pemiciosus (Comstock), in a North Carolina apple orchard and this status persisted with little change during the coldest winter months. Small numbers of all other life stages also hibernated. Development and survival of scale insects, which were field collected from November to February and placed under long and short daylengths at constant 20°C, did not appear to be affected by daylength. This information, plus evidence that diapause was not induced by long and short daylengths at constant 15 and 20°C, indicates that San Jose scale hibernates in a nondiapause state of dormancy and the dormancy is temperature dependent.