Pests on Dwarf Arctic Willows
- The tender leaves and bark make aphids a common pest of dwarf arctic willows. Aphid pests appear as small, black spots on the bark, stems and leaves of an arctic willow. This is particularly true when temperatures are mild and moisture levels are high, either from humidity or overhead watering. Ground irrigating with a drip system will eliminate excess moisture on the foliage of the shrub. Once aphids have invaded your dwarf arctic willow, treat with an insecticide, according to directions, that is formulated for the pest.
- One of the few pests that will eat arctic willows in their native environment is the woolly bear caterpillar. This unique pest has the ability to be frozen solid and survive. Woolly bears, like other caterpillars that feed on dwarf arctic willows, devour the buds and leaves on the shrub. Later in the growing season, arctic willow foliage develop a toxicity that cause caterpillars to avoid the shrub. Early in the growing season, regularly examine your dwarf arctic willow for caterpillars. When you discover one, take it to your local university extension office for identification. The agents at the extension office can effectively guide you on the best remedy to eradicate the pest. A general caterpillar treatment is to apply Bacillus thuringiensis, a natural soil bacteria that is safe for humans and animals but repels or kills caterpillars.
- Willow leaf beetles will appear in May, feasting on your arctic willow and laying eggs. Within a few weeks, your dwarf arctic willow will be depleted of foliage and have an abundance of small, oval-shaped, dark greenish-blue beetles. The beetles will stay on the shrub, consuming the leaves, throughout the growing season unless you spray shrub with an insecticide designed to kill willow leaf beetles. The insecticide should kill both beetles and larvae. Effective chemicals include permethrin, chlorpyrifos, bifenthrin or pyrethrin.
- Though they don't sting, sawflies resemble a wasp. Willow sawflies and their larvae feed on the foliage of arctic willow shrubs. Not only will the larvae and adult sawfly consume your willow leaves, but these pests are not selective and will spread to other plants. The larvae can cause the most damage, looks similar to a caterpillar but without the fuzz and is black with yellow spots. Spray your dwarf arctic willow with an insecticide for sawflies and sawfly larvae. If you discover gall on your willow leaves, tiny bumps where a female sawfly laid eggs, prune the infected branches off and burn them or place them in the trash. Total elimination of the gall-infected branches from your property is essential in getting rid of these pests.
