As the name implies, these are insects that cover themselves with a waxy, "wooly" covering to protect themselves during a part of their life cycle. As aphids, of course, they are sucking insects that draw sap from the plant for their nourishment. There are many species of wooly aphids that are pests of a large number of trees including silver maple, ash, alder, apple, pear, hawthorn and serviceberry.

Most wooly aphid species spend their time on alternate hosts. They may lay their eggs on a host plant where they can overwinter. In the spring, the female aphids, after a generation or two develop on the first host, can then fly to the secondary host species, lay eggs and start things all over again. Like many aphid species, wooly aphid females can produce eggs without mating with a male. The offspring are considered clones of the one parent since they are not the result of the combination of two sets of genetic materials.

The most common sign is, of course, the presence of the insect itself. In severe infestations, there is a mass of white, woolly filaments extending from the branch or twig. These growths are primarily there as a deterrent to insect predators.

Another sign that is common to most aphid infestations is the presence of a black, powdery covering on leaves beneath where the insects are feeding. This is sooty mold, a fungus that grows on the sugar rich droppings of the insects.

The key symptom for some of the aphids is the presence of distorted, twisted leaves. When they feed on the leaves and remove water and sap, the leaves will crumple and become misshappened.

The primary damage done by wooly aphids is the removal of sugars and carbohydrates from the plants through their feeding. In very large, long-lasting infestations, this can weaken twigs and, sometimes, branches of the plants. In combination with other stresses such as droughts, this may result in the death of certain plant parts.

Since these insects are rather sedentary, it is relatively easy to see when they have built up to large numbers. They do not fly or run away and hide. So, treatment can be rather straightforward once you determine that your threshold has been reached.

Insecticidal soaps may be effective when sprayed onto the aphids. Soaps tend to melt the waxy coating on the skin of insects causing them to dry out and die.

Other standard insecticides are also labeled for use with wooly aphids.

Note: We have provided some general information and observations on this topic aimed at the home gardener. Before you take any serious action in your landscape, check with your state's land grant university's Cooperative Extension Service for the most current, appropriate, localized recommendations.

Types of Insects

"Name That Bug Page"

Note: We have provided some general information and observations on this topic aimed at the home gardener. Before you take any serious action in your landscape, check with your state's land grant university's Cooperative Extension Service for the most current, appropriate, localized recommendations.

 

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