Caterpillars & Birch Trees
Several caterpillars use birch trees as sources of food during their larvae stage. The caterpillars eat the leaves of the trees while they grow big enough to go into their pupate stage before emerging as moths.
The birch leaf roller, Epinofia solandriana L, is a small caterpillar commonly found in south-central Alaska. The insect gets its name thanks to the older caterpillars that start to roll the leaves as they feed on them. Forest tent caterpillars may also feed on birch trees while building nests to live in while they eat and grow bigger.
While leaf rollers cause little long-term damage to birch trees, the tree can become unsightly. Forest tent caterpillars also cause little permanent damage, but they can cause the tree to produce smaller leaves to replace the ones the caterpillars ate. Tree growth rates can decrease because of the defoliation, causing the trees to become more susceptible to other pests.
Natural predators, including the parasitic fleshfly, help control the insects by eating forest tent caterpillars in their cocoons. Insecticides may be required if birch leaf rollers infest a tree for more than two years in a row.