Red maples are the most frequently planted street tree in the Eastern US and none of
them seem to be very healthy. Any red maple you look at it seems is covered in gloomy scale and in declining health. Gloomy scale is the worst pest of red maple street trees. Often tree bark will be entirely covered with scale and you wonder how the trees hang on at all.
Right now gloomy scale crawlers are active on trees in Raleigh. There is one generation of gloomy scale per year but crawlers emerge gradually over the course of about 6 weeks. Thus management is difficult since it is impossible to make insecticide applications when all the crawlers are out and vulnerable. We are studying the ecology and management of gloomy scale on urban trees to help protect urban forests. We have found a number of systemic insecticides and insect growth regulars to be effective against armored scales. These are listed in the armored scale insect note.