Stomacoccus platani
Pest description and damage Scale insects are small (less than 0.125 inch in length) soft insects that live beneath waxy scales. These insects are often identified by the shape and size of their scales, the description of adult males and females, immature crawler stage, color of eggs, and host plant preferences. The sycamore scale is tiny (adult length from 0.05 to 0.06 inch). This insect causes leaves to develop small yellow spots. Eventually, the leaves become pock-marked with numerous small, brown, necrotic (dead) spots that may be confused with leaf spot fungi. Leaves infested while young are often smaller and disfigured. Premature leaf fall also may occur, although other factors may cause early leaf drop. This scale species also feeds on bark, causing twig dieback.
Biology and life history The scale overwinter in crevices on the bark. Eggs are laid in late winter in cottony masses. Egg hatching coincides with leaf budbreak and continues until the leaves are expanded fully. The crawlers move from the bark to the new foliage to feed. Sycamore scales frequently align themselves along the major veins of the leaf to feed. They remain here until maturity, and then migrate back to the bark to lay eggs for a new generation. There may be three to five generations per year.
For biology, life history, monitoring and management
See "Scale insect" in:
Management-chemical control
See Table 1 in: