Damage
The areas of leaves that are consumed by the amber marked birch leafminer larva turn brown. Because people often do not see the early signs of birch leafminer feeding, it often appears the tree has suddenly dried up or become diseased. This browning is caused by the outer layers of the leaf drying out after the leaf miner larva has consumed the green tissue between the outer layers of the leaf. Early mines appear as light green or whitish discolorations on the leaves. Larvae sometimes can be seen easily when leaves are held up to sunlight, especially as the mines and larvae grow larger. Feeding over several weeks causes the blemish to take on a blister-like appearance. A single leaf can contain as many as 40 larvae whose mines may merge to destroy the total photosynthetic area of the leaf. Heavy infestations of leafminer larvae can seriously affect a tree's photosynthetic capacity. Repeated attacks will generally cause stress which may induce susceptibility of the tree to other injurious agents.
Read more about this topic: Birch Leafminer
Famous quotes containing the word damage:
“For most Northerners, Texas is the home of real men. The cowboys, the rednecks, the outspoken self-made right-wing millionaires strike us as either the best or worst examples of American manliness.... The ideal is not an illusion nor is it contemptible, no matter what damage it may have done. Many people who scorn it in conversation want to submit to it in bed. Those who believe machismo reeks of violence alone choose to forget it once stood for honor as well.”
—Edmund White (b. 1940)
“If every man possessed everything he wanted, and no one had the power to interfere with such possession; or if no man desired that which could damage his fellow-man, justice would have no part to play in the universe.”
—Thomas Henry Huxley (1825–95)
“I learned early to understand that there is no such condition in human affairs as absolute truth. There is only truth as people see it, and truth, even in fact, may be kaleidoscopic in its variety. The damage such perception did to me I have felt ever since ... I could never belong entirely to one side of any question.”
—Pearl S. Buck (1892–1973)