There is generally only one generation per year in the Central Valley. However, in some years two generations have been detected. It is about 0.25 inch in length at maturity and has one generation per year. It is found in the warmer interior growing areas. High temperatures early in summer will increase mortality of immature stages of European fruit lecanium.
Soft scales molt twice before they reach maturity.
The stage just before the adult one is frequently referred to as the rubber stage. In this stage, the scales remain soft, somewhat translucent, and are still susceptible to parasitism and insecticides. Upon molting to adults, the shell hardens and becomes opaque. These scales are normally kept under control by native parasites. Because of the increase in chemical treatment in pistachio, natural enemies of scales are more frequently destroyed, and soft scales are becoming more prevalent.