The Leaf crumpler larva is around an inch long, with a green-grey color with purple markings at each segment. The adult is a small moth with brown and white stripes along its wings. The caterpillars build web tubes on twigs which incorporate leaf fragments as they feed. The tube can be 1.5-2 inches long by the time the caterpillar is mature. Damage and nests are at their peak in July and August.

The name, Pear slug, is a misnomer; these are not true slugs but sawfly larvae. The shiny, green to orange larvae can be up to a half inch long and feed by skeletonizing leaves. Larvae feed on the lower surface of pear, cherry and plum. There are two generations per year with overwintering occurring as a pupa. Adults emerge in early summer and lay eggs which mature, pupate and emerge as adults by August-September. New larvae from the summer generation will feed then pupate for the winter.

Lace bugs are flat gray sap-feeding insects with clear, ornate, lacy wings; nymphs are spiny and wingless. Both stages 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 under bark or in leaf litter. The eggs hatch in early spring and the nymphs begin to feed on plant sap. There are several generations each season. Initially, numbers are so small that feeding symptoms are not noticed until the population peaks in late summer. When abundant, feeding can make plants unsightly and may cause premature leaf drop.

Oystershell scales are about 1/10 inch long and resemble crusty accumulations of oyster shells on the bark. Their drab, bark-like appearance makes them easy to overlook, even on close inspection. Heavy infestations can kill twigs or branches. This scale overwinters in the egg stage under the waxy covering of the female. The eggs hatch and the crawlers are active from late May to early June.