Date of this Version
Voles damage trees in several ways. They eat the roots, and if the damage is light the apple tree may not show any obvious problem, but the amount of yield loss can be great. If the voles girdle the tree (cut the bark at or near the soil line), they cut the xylem tubes and this will reduce the amount of water and nutrients taken into the tree. When this happens and moisture stress is high, the tree will turn yellow in July (summer months). If injury is serious, the tree top may die, and if the girdling is severe, little or no food (carbohydrates) will be returned to the roots, so the roots die. Usually, the whole tree dies in six months, a year, or sometimes two years. Control has been very effective since Endrin has been used. Only once in a while do I see a dead or dying tree in an Endrin-treated orchard.