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Cornell University : Cornell Cooperative Extension
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| Yates Association |
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Bronze Birch Borer |
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The bronze birch borer is a destructive pest of paper birch, European white birch, yellow and gray birch and plants in the poplar family. Many tree experts report that the borer is nearly inevitable in the life of white birches, and for this reason we recommend selecting alternative trees such as River Birch which are resistant. The bronze birch borer is largely responsible for the appearance of dead and dying birches in the landscape. The larval stage damages trees by boring into the trunk and larger limbs. The first signs of damage are the dying back of branches near the top of the tree. Within 2-3 years the entire tree may be killed. Birch trees under stress from poor soil fertility or weakened by drought are much more susceptible to birch borer. Adult birch borers emerge in May or early June. Eggs are laid in cracks or crevices or wounds in the bark. Recent research suggests pruning birch in the spring may increase risk of borer. And - avoid wounding your birch with lawn mowers or other equipment throughout the year. Birch borer can be discouraged by keeping trees well watered, fertilized and in a vigorous condition. Once birch borers are in a tree they can be difficult to control. Sometimes borers can be removed manually by slitting the tree and piercing the bored with a pin. Severely infested trees should be cut down and destroyed. When one or two branches are infested prune out and burn or dispose of the material. Preventative spraying by a certified arborist can also be done in May to discourage the adult stage. Cornell
Cooperative Extension Yates Association |
