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:
“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)
“A cure by regression is homeopathic, like healing the damage done by ministers and ignorance with stupidity and Jesuits.”
—Franz Grillparzer (1791–1872)
“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)