Leaf hoppers suck on the sap supply of the leaves.

Leaf rollers cause the leaves to curl up and die.

Trees injured by fire fall easy prey before the attacks of forest insects.

It takes a healthy, sturdy tree to escape injury by these pirates of the forests.

There are more than five hundred insects that attack oak trees and at least two hundred and fifty different species that carry on destruction among the pines.
Insect pests have worked so actively that many forests have lost practically all their best trees of certain species.