Pests and Diseases Viewer
Caused By:- The Moth Operophtera brumataDescription
The Winter Moth is an unusual moth in that it is probably the only moth that is active in the winter in temperate climes. Their caterpillars eat holes in leaves, blossom and fruitlets which are often misshapen if they continue to develop. Apart form apples, pears, plums and cherries many ornamental trees and some perennials are attacked as well, including oak, sycamore, hornbeam, beech, dogwoods, hazels and elms. They are first noticed in the early spring when the new leaves are unfolding and are often hard to spot as they bind the leaves with silken threads. The holes eaten in the leaves often only become apparent when the leaves are fully opened. Severe attacks will weaken plants. Wingless and flightless females and males that can fly emerge from pupae in the soil during October to January and the females crawl up trunks to begin laying eggs on the buds and branches after they are mated. The males have a wingspan of 28 to 33 mm which is a grayish-brown forewing with lighter hindwings. The adults are active at night throughout the winter and the males are attracted to light. After hatching, the young larvae produce silken thread that can carry them in the wind to new areas. This method of dispersal is known as - ballooning - in some circles. The caterpillars are green with pale lines on the sides and a darker one along the top. They move about in loops as they only have two pairs of clasping feet. They will feed until about mid-June when they reach a size of about 25mm and enter the soil to pupate. Picture from Wikimedia Commons.
This pest can be reduced by placing a sticky grease band or sticky insecticidal bands around the tree trunk in October to intercept the females. Many birds, especially tits, feed their chicks with large numbers of winter moth caterpillars during the spring. Spraying is also possible when the leaves are emerging, but before flowering. The bacterium Bacillus thuringiensis can also be used as a biological control.