College of Agriculture & Natural Resources

• Phytophthora root, crown, and collar rot

  Crown and collar rot are often and mistakenly used interchangeably. Collar rot refers to infection that affects the bark tissue of the scion portion of the tree at or just below the soil line, whereas crown rot affects the bark tissue of the rootstock portion of the tree.

• San Jose scale

  Adult males are minute, winged insects about 1 mm long and golden brown with a reddish tinge. Scales may be either disk-shaped or oval, and are composed of concentric rings of gray-brown wax radiating from a tiny white knob.

• Spotted wing Drosophila

  Spotted wing Drosophila can be distinguished from other vinegar flies by spots on the wings of male flies, and by the ovipositor on female flies.

• Skeletonizers

  The adults of the skeletonizers are brown and short, with transverse bands on each forewing. The larvae are yellow to pale green with numerous hairy discs on each segment of the body.

• Pear thrips

  Adult is slender and brown, with short antennae and a swelling behind the head; the wings are long and narrow, with fringes of long hairs.

• Forbes scale

  Round or elongate gray scale with a raised reddish area in the center, which distinguishes it from the San Jose scale.

• Stink bugs

  The adult has an oval shield-shaped body, grayish or brownish in color; a spur is present on each side of its thorax. Eggs, grouped in masses of 20 to 30, are in the shape of small barrels. They are gray, cream or gold-colored, decorated by a ring of small hairs.

• 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.

• European apple sawfly

  The adult looks similar to a small, orange-brown wasp with the ventral side and legs orange in color. It has transparent wings with many veins. The egg, oval and translucent, is inserted into the receptacle of the flower.

• European fruit lecanium (Brown apricot scale)

  The adult female scale is nearly hemispherical and shiny brown, with several ridges along the back. Nymphs are light colored.

• Alternaria fruit rot

  The disease appears as velvety dark green to black, circular, sunken lesions on mature fruit; the infected tissue is firm and brown. Disease is typically associated with over-ripe or damaged fruit, or fruit held in storage.

• Codling moth

  The adult's forewings are striped with fine brown-gray lines and a distinctive bronze to brown-black oval spot at the tip. Eggs are laid on the leaves or fruit.

• Eastern tent caterpillar

  The adult is reddish brown with two white, 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 yellow line on their back.

• 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.

• Click beetles

  The click beetle is dark-colored its body is hard and elongated it has a characteristic pair of spurs and sometimes colorful markings on its thorax.

• 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.

• 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.

• Snowy tree cricket

  Adult somewhat resembles a field cricket, but is pale green in color and has a longer, more slender body and smaller head. Antennae are much longer than the body; males have stiff veins in their flat wings.