Winter moth caterpillars eat holes in the leaves, blossom and developing fruitlets of many tree fruits, ornamental trees and shrubs. Severe attacks can weaken plants. Extensive damage to fruit trees can affect crop yield and quality.
Winter moth is a general name that can be used for a number of species that have adult moths that emerge and lay eggs between November and April. These moths have wingless females that emerge from pupae in the soil and crawl up trunks to lay eggs on branches.The most important are the winter moth (Operophtera brumata), mottled umber moth (Erannis defoliaria) and March moth (Alsophila aescularia). The caterpillars of these moths hatch in the spring as buds are opening and they will attack most types of tree fruit and many deciduous trees and shrubs. The main fruit trees attacked are apples, pears, plums and cherries. Many ornamental trees are also attacked, including oak, sycamore, hornbeam, beech, dogwoods, hawthorns, Sorbus, roses, hazels and elms.