Wooly Aphid
Meet the Wooly Aphid
The wooly aphid can occur on many shrub and tree species. They are pear-shaped, small insects, about one eighth of an inch in length. They often are covered with waxy, white strands that make them appear wooly, hence their name. They usually have two host plants – one primary host that they will feed on in the winter, and a summer host they feed on during the warmer months. They usually spend the winter as eggs within the bark of a tree. The eggs hatch in the spring, and each female will produce hundreds more eggs, and their population grows quickly.
After a couple generations on their winter host plant, winged females are born, and they fly to find their secondary or summer plant host. They will stay on that host until the end of summer, all the while producing more eggs. Even though they usually have two hosts, most aphids can live only on the second host plant, if the would need to.
The wooly aphid feeds by inserting its mouth parts into its hosts' tissue and withdrawing sap. They generally feed on roots, bark, twigs, buds and leaves. You can tell when your plant is a host, because it will display low vigor, poor growth, yellowed foliage and curled and twisted leaves. If a large number of aphids attack unhealthy or young trees, they can cause considerable damage. As a rule, severe infestations don't occur often, and they are generally slowed down by the aphids' natural enemies. There are symptoms they leave behind, in addition to the damage to the plants. These include such things as shed skins and accumulations of wax on bark, twigs and leaves.
After feeding on sap, wooly aphids excrete a sticky, sweet waste called honeydew. It can coat bark and leaves, making them look shiny and wet. Honeydew is hard to remove, and there is also a black fungus that can grow on it.
There are natural predators that can keep the wooly aphid under control. Wasps, hover flies, lady beetles and lacewings are all helpful in keeping the aphid population in check. If you have a smaller area of infestation, you can prune and destroy the infected plant parts.
You can also use insecticides to reduce wooly aphid numbers in your garden. Systemic insecticides manage them more effectively than contact insecticides or soap, since the latter do not get all the way insides the wax or curled leaves. The parts of the plant that were already affected will stay deformed and curled or waxy, even if your wooly aphid infestation is treated. If you can't treat your garden yourself, you can call in a reputable lawn care service, since they have experience in ridding areas of garden pests.