When the crawler stage occurs differs with the scale species and the weather. After the insect settles and secretes wax, it is largely impervious to insecticides. These materials generally are translocated within the plant in highest concentrations to the newer growth. Armored scales Many people do not recognize these scales as insects. Instead, they think they are part of the tree or shrub itself.
Mature scales lack a distinct head, legs or antennae.
Eggs mature underneath the female scale. The first larval stage hatching from the egg is called the crawler stage. This is the only mobile life stage other than the adult male, which is rarely seen and lives only a few days. Crawlers move about for several days before permanently settling down on the plant to feed. Crawlers and very young scale insects are the life stages most susceptible to insecticides.