What Are the Little White Moths in a Cedar Tree?
- The gypsy moth is a common pest of many varieties of trees including cedars. Only the female moths are white but they are often found around the trees. The females also have small dark markings on the wings but they do not fly. Only the brownish black males fly. The moths cause no damage to the cedar trees because they do not feed but the larvae are extremely damaging pests. Moth larvae must endure several development changes called instars. The larvae go through five instars as males and six for females. Each instar feeds on foliage at increasing rates.
- The young caterpillars hatch in April or May and are carried by the wind to other trees or parts of the host tree. They change color several times and grow from 1/16 inch to 5/8 inch. Up to the fourth instar the caterpillars feed on the foliage at the top of the cedar. They move lower and cause the most feeding damage after that change. Young caterpillar feeding creates tiny holes in the foliage but once they get older the entire spray of leaves will be devoured. Since 1980 the gypsy moth has defoliated over a million forest acres annually.
- Gypsy moths are not native to North America but originated in Europe and Asia. They were introduced in 1869 by a French scientist, E. Leopold Trouvelot. The moths quickly spread and caused their first outbreak in 1889. The first outbreaks were near Trouvelot's neighborhood in Boston, Massachusetts. Infestations fluctuate every other year with a year of increase followed by a year of decline in a cyclical manner. Over the past 100 years the moth has been studied and monitored. Many methods of control are consistently applied, but the moth's range is still spreading.
- Gypsy moth larvae should be sprayed when they are young during the second and third instar. They are too tiny in the first and tend to get blown around. There are microbial, biological and chemical sprays that have some effectiveness if they are applied by a professional. A professional is necessary because all areas of the tree need to be treated and the average homeowner doesn't have the necessary equipment. You can also use sticky traps to catch migrating caterpillars.
