San Jose Scale San Jose Scale Click Open to view a picture. Close the current picture before viewing another. Scale crawler on tape trap Drawing of mid-season and black cap stage The San Jose scale, Quadraspidiotus perniciosus , is a pest of fruit trees, but it attacks many other trees as well as shrubs. Once established, most scale insects are difficult and expensive to control. Description and life cycle Female scales are very prolific and over a 6-week period can produce approximately 400 young.
Crawlers move around for a short period in search of a suitable place to settle.
It takes 25 days for males to mature and 31 days for females. There are two to three generations of the San Jose scale each year. Males emerge and mate at petal fall. First-generation crawlers begin appearing in early June in southern areas and continue for a month. These crawlers develop into mature adults by late July.