A variety of sampling methods have been developed for assessing spongy moth populations and forecasting potential damage to host trees. Sampling methods have been developed for each stage of the spongy moth life cycle:

Larvae: Burlap or sticky bands placed around the main stem of the tree can be used to trap spongy moth larvae and pupae. Spongy moth larvae seek shelter under the bands during the later feeding stages and often will pupate under these bands. Larval densities can vary greatly from day to day, and even during the day.

Adults: Female spongy moth adults do not fly but attract the male moths by releasing pheromone. This pheromone has been synthetically reproduced and is used to lure male moths to a variety of sticky or bucket-like traps. This is an effective method for detecting the presence of low level spongy moth populations and is widely used in the United States and Canada (Gage et al. 1990). Because this pheromone is so efficient, spongy moth pheromone traps are less effective during periods of high populations when they tend to become saturated with moths.

Egg Masses: Spongy moth lay their eggs in masses of up to 1,000 eggs on the stems and branches of trees, as well as on the forest floor and objects in July and August each year. They will remain in the egg mass until hatch begins sometime in April or May the following year. This provides the longest period for assessing spongy moth populations and is considered the most reliable method. Egg masses are easily counted, especially following leaf fall in the autumn, and old egg masses are generally easily distinguishable from new egg masses allowing for more accurate counts of the current year population.