College of Agriculture & Natural Resources

• Black cherry aphid

  Adults and nymphs are shiny black soft-bodied insects; adults may or may not have wings. Nymphs are smaller, but generally similar in appearance to the adults.

• Black knot

  Black knot usually develops over two seasons. The disease first appears in late summer or autumn as an olive-green swelling on new shoots. Disease develops rapidly the following summer, forming a characteristic dark, course-textured warty knot.

• Cherry leaf spot

  Lesions begin as small, circular red to purplish spots on the upper leaf surface. Spots enlarge as they grow older, typically coalescing and turning brown. Lesion centers may eventually drop out to give the leaf a "shot-hole" appearance, particularly on plum.

• White peach scale

  Adult female is creamy-white to reddish orange, and covered by a round waxy scale that is grayish to brownish white. Adult males are tiny yellow 2-winged insects, and nymphs are oval and white to orange.

• Green stink bug

  Stink bug adults have a broad, flattened, shield-shaped body and a narrow head. The green stink bug is uniformly grass-green.

• Green fruit rot

  Both fungi attack the blossoms but rarely invade the twig.

• Dusky stink bug

  Stink bug adults have a broad, flattened, shield-shaped body and a narrow head. The dusky stink bug is dark brown, with sharp shoulder projections.

• Fall webworm

  Adult is a white moth with dark spots on the wings, which may be less distinct in northern specimens. The pale yellow larva has a dark head and dark tubercles with clumps of hairs.

• Fruittree leafroller

  The adult is red-brown with mottling. The translucent green caterpillar has a reddish to dark brown head and an amber to pale green thoracic shield edged with brown.

• Rose chafer

  The rose chafer is a light tan beetle with a darker brown head and long legs. It is about 12 mm long. There is one generation per year.

• Pear plant bug (Green apple bug)

  The adult pear plant bug is brownish yellow with two dark bands on the thorax and the extremities of its anterior wings are yellowish in color.

• Plum rust mite

  Plum rust mites (PRM) generally restrict their feeding to new foliage, causing these leaves to brown and roll upward longitudinally

• Dock sawfly

  The adult is bluish black with red legs. The larva is a smooth velvety green worm with white legs and a dark head.

• Climbing cutworms

  Adults are dark brown or grayish colored moths. Larvae tend to be smooth caterpillars with few hairs, brown or black head capsules, and bodies a dull gray-brown background color with stripes, spots, or dark brown, black, yellow or white splotches.

• Forest tent caterpillar

  Adults are reddish brown with two brown, transverse-parallel bands. Masses of shiny black eggs are laid in a ring around twigs. Larvae have long silky hairs on their body and a row of elongated spots along the back.

• Pearleaf blister mite

  The adults are very small and cannot be seen without a 15X hand lens; the body is white and elongate oval in shape, like a tiny sausage.

• Variegated leafroller

  Adult is grayish magenta with dark brown bands on the middle and end of the forewing. Larvae are pale green with yellowish green heads.

• Perennial canker of stone fruit

  Small twig infections are usually found around winter-killed buds, leaf scars, and picking and pruning injuries. They appear as sunken discolored areas with alternating zonation lines and may ooze amber gum unless the twig is killed.

• Oystershell scale

  The adult female remains immobile under a small brown scale in the shape of an oyster shell attached to the bark of branches. The white and oval eggs are laid inside the scale and crawlers emerge in the spring during the petal fall stage of apple.

• Pear psylla

  Adults resemble very small cicadas and can be reddish brown or tan to light brown. Smaller, wingless nymphs are yellow with red eyes, flat and oval in shape, and develop within a clear honeydew drop.