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:
“There is such a thing as food and such a thing as poison. But the damage done by those who pass off poison as food is far less than that done by those who generation after generation convince people that food is poison.”
—Paul Goodman (1911–1972)
“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)
“Instead of asking—”How much damage will the work in question bring about?” why not ask—”How much good? How much joy?””
—Henry Miller (1891–1980)