Sheta, I.B., & Jenser, G. 1970 Kaliforniai pajzstetün (Quadraspidiotus perniciosus Comst.) végzett fenológiai vizsgálatok. [Phenological studies of the San José scale, Quadraspidiotus perniciosus Comst.]. Növényvédelem 2: 76-81.

Notes: The quiescence of over-wintered, L1 larval instars of the San José scale ends nearly uniformly in the spring, which makes it easier to determine the optimal date of control measures. Individuals of developmental instars of the summer generation may be found until June.