Azalea caterpillars have one generation each year during August and September. Small larvae skeletonize leaves, large larvae consume entire leaves. In sufficient numbers they can defoliate plantings in a short time. These hairy caterpillars have 7 light stripes along the body; its head and legs are red. Full-grown caterpillars are about 2 inches long. Azaleas are the preferred host but the caterpillars also feed on blueberry foliage.

Fall cankerworm is a looper caterpillar that can vary from light green with yellow stripes to green with a dark stripe down the back. Overwintering masses of about 100 eggs hatch in later April or early May; small caterpillars chew small holes in young leaves at branch tips. Larger loopers leave only the midrib and major veins. Fall cankerworms are about an inch long when full grown. Mature larvae descend from trees on silk threads to pupate in the soil. They emerge as adults during periods of freezing temperatures to mate and lay eggs on host plants. There is one generation each year.

Azalea lace bugs are 1/8 to 3/16 inches long sap-feeding insects with clear, ornate, lacy wings; The immature stages (nymphs)are spiny and wingless. Adults and nymphs live on the lower surface of leaves. As they feed, they leave tiny yellow to white spots on leaves and dark, varnish-like waste spots on the under sides.

These lace bugs spend the winter as eggs inserted into leaves. The eggs hatch in early spring and the nymphs begin to feed on plant sap. Development from egg to adult takes about 5 weeks. There are several generations each season. Usually, there are only a few insects in the first generation so feeding symptoms are not noticed. Numbers and damage to plants increase to a peak in late summer. When abundant, feeding can make plants unsightly and may cause premature leaf drop.

Azalea lace bug damage

Southern red mites are tiny (1/50 inch) arthropods with a dark red or brown color. They live on the underside of leaves and use needle-like mouthparts to remove the contents of individual cells. This produces tiny white to yellow spots on leaves, sometimes called flecking or bronzing. Infestations are usually most serious during cool periods of spring and fall.

Aphids are soft-bodied insects that use their piercing sucking mouthparts to feed on plant sap. They usually occur in colonies on the undersides of tender terminal growth in the spring. Heavily-infested leaves can wilt or turn yellow and senesce prematurely because of excessive sap removal. While the plant may look bad, aphid feeding generally will not seriously harm healthy, established trees. Some plants are very sensitive to feeding by certain aphid species. Saliva injected into plants by these aphids may cause leaves to pucker or to become severely distorted, even if only a few aphids are present. Also, aphid feeding on flower buds and fruit can cause malformed flowers or fruit.

Aphids produce large amounts of a sugary liquid waste called "honeydew". The honeydew that drops from these insects can spot the windows and finish of cars parked under infested trees. A fungus called sooty mold can grow on honeydew deposits that accumulate on leaves and branches, turning them black. The appearance of sooty mold on plants may be the first time that an aphid infestation is noticed. The drops can attract other insects such as ants, flies, and wasps that will feed on the sticky deposits. For more information, see Entfact 103.

Emerald ash borer is an invasive species that feeds on all ash species and some closely related plants. The adult is a small metallic green beetle and the larva is a flat headed borer. Larvae feed in the cambium of ash plants and are 100% lethal for untreated ash trees. Common symptoms including branch suckering, die back, increased woodpecker feeding, and "D" shaped exit holes in the bark. There is one generation per year, with adults active in the early season and larvae overwintering in their last instar. For more information, see Emerald Ash Borer (EAB) on the University of Kentucky Entomology webpage.

Both the caterpillar and adult of the Wood leopard moth are very distinctive. The caterpillar is the damaging stage, feeding under the bark of host trees. It is a white-orange color with numerous spots on its body. The adult is white with six black dots on the thorax and black markings on the remainder of the body. Adults may be active June-September and larvae feed inside of plants for 2-3 years.

These two round-headed borers, the Redheaded ash borer (top) and the Banded ash borer, are not serious pests of ash. They take advantage of dead and dying plants to lay their eggs. Specimens are often found when people bring ash firewood in for winter fireplace use. The adults are one half inch long. Redheaded ash borers have reddish orange coloration and horizontal yellow stripes on the back while Banded ash borers are black-brown with two cream ovals and two stripes on the back.

Ash flower gall mites are small, banana shaped mites that infest the male flowers of ash. As the mites feed, the flower buds will develop galls that start green but eventually turn brown. They resemble numerous pom-poms in the plant. This is strange to see but causes no damage to the plant and is more of a curiosity.