Common name: Cottony maple scale
Scientific name: Pulvinaria innumerabilis
Hosts: The primary hosts of cottony maple scale are silver maple (Acer saccharinum) and boxelder (Acer negundo). It can also infest other maples (Acer), white ash (Fraxinus americana), hackberry (Celtis), dogwood (Cornus), beech (Fagus), apple (Malus), oak (Quercus), linden (Tilia), elm (Ulmus), black locust (Robinia), and honey locust (Gleditsia). This insect is native to North America.
Scale insects are unique and look quite different from other insects. In their juvenile growth stage, they are referred to as crawlers. As crawlers, they are highly mobile, six-legged, have no protective cover, and are very small (<1/32 inch). At maturity, scale insects are immobile, have a covering over their body and are large enough to see without a magnifying glass.
Scale insects fall into two categories, soft scales and armored scales. Cottony maple scale is a soft scale. The soft scales are usually larger than armored scales. They cover themselves with waxy secretions. Most soft scales overwinter as immature females. In most years, this insect is considered a minor pest. Every few years, the population rises dramatically and does more damage. Natural predators often rise in a reaction to the increased population and, over time, they reduce the pest population significantly.