It is an abundant species in Europe and the Near East and a famous study organism for evaluating insect population dynamics.

After the initial frosts of late fall, the females emerge from their pupae, walk to and up trees and emit pheromones in the evening to attract males.

[6][7] The forewing ground colour of the winged males varies from grey-yellow to beige-brown or occasionally slightly reddish-tinted.

[8] The flightless female has a brownish-grey body with rudimentary wing stubs that are brown to grey and have dark bands.

[10] In North America, the winter moth can be confused with the related native species, the Bruce spanworm (Operophtera bruceata).

Locally milder winters, as part of global climate change, may be allowing expansion of afflicted territory.

[14] Winter moth larvae (caterpillars) emerge in early spring from egg masses laid near leaf buds after a series of days in which the daytime high temperatures reach around 10 °C (50 °F).

[18][19] Research conducted in the Netherlands indicated that as climate warming is causing spring temperatures to become warmer sooner, some of the winter moth eggs were hatching before tree leaf buds – first food for the caterpillars – had begun to open.

Because hatch timing is genetically controlled, the moths are evolving to resynchronize with bud opening by delaying the response to the temperature trigger by 5 to 10 days.

[20] Larvae prefer oak and apple, but also feed on maple, birch, hornbeam, chestnut, hazel, quince, beech, larch, poplar, cherry, pear, rose, raspberry, blueberry, willow, elm, and other leafy trees and shrubs.

This proved successful, so more fly releases have taken place at sites from southeast Connecticut to coastal Maine.

Once this is achieved the winter moth density will decline and leaf defoliation will be reduced to levels not as harmful to the trees.

[23] Management of the winter moth in Massachusetts using biological control with C. albicans is showing positive results.

When the eggs are newly hatched in late March and early April Bt (Bacillus thuringiensis) is a safe and effective way to control caterpillars.