Tiny nymphs or crawlers hatch and emerge from under their protective covering around mid-June. They're flat, oval and pale green to brown. A wide variety of fruit trees, ornamental shrubs and trees can be affected. Later, they move to older wood, turn brown and settle in for the winter. Plants show signs of a general decline often before the crawlers or adults are even noticed.
Brown scale leave behind honeydew, a sticky, undigested sap.
Eventually, this sap grows a dark, sooty mold on leaves and stems. After their shells have formed, scrub scale off with a brush and soapy water or rubbing alcohol. Remove and destroy heavily infested branches. Horticultural oils sprayed when the plant is dormant suffocate adult scale and eggs. Biological controls include parasitic wasps and soldier beetles.