A. LEAVES EATEN

1. Webbing on outer branch present in summer and early fall; webbing enlarges as season advances; caterpillars usually seen within webs.

   FALL WEBWORM

2. No webbing
   1. Caterpillars present and found in groups feeding on edges of leaflets.
      1. Full-grown caterpillars hairy, dark purple to black, often with a white stripe along sides.

         WALNUT CATERPILLAR

      2. Full-grown caterpillars hairy, brick red to black with yellow stripes running the body length; a yellow bar present behind the head capsule.

         YELLOW NECKED CATERPILLAR

   2. No caterpillars present
      1. Insects rarely seen feeding; oblong holes between veins in leaflets.

         MAY BEETLES

      2. Partially or completely eaten leaves; green or brown jumping insects may be seen.

         GRASSHOPPER

B. LEAVES DAMAGED BUT NOT EATEN

1. Young leaves drooping, later turn brown or black.

   FROST DAMAGE

2. Leaves stippled, often with some surface distortion; many dark-colored insects may be present on lower surface of leaflets, some with lacy appearance.

   WALNUT LACE BUG

3. Leaves crumpled or distorted
   1. Leaf stem or leaflets severely crumpled and distorted, especially in spring; later in the season damaged parts may turn reddish and with a velvety texture.

      MITES

   2. Leaflets cupped or moderately distorted, numerous greenish-colored 1/16- to 1/8inch-long insects may be present on under surface of leaflets.

      APHIDS

4. Leaves with spots or blotches
   1. Leaflets pale with irregular dark brown to black spots, often bordered with yellow.

      WALNUT ANTHRACNOSE

   2. Leaflets with white, "powdery" substance on upper surface.

      POWDERY MILDEW

   3. Leaflets with small white circular spots on under leaf surface.

      DOWNY LEAFSPOT

   4. Leaflets with regular brown spots, often with concentric rings like a "bulls eye" target.

      TARGET LEAFSPOT

1. Nuts covered with small, dry, dark, sunken areas.

   WALNUT ANTHRACNOSE

2. Nuts with large, moist, dark, sunken areas.

   HUSK MAGGOT/HUSK FLY

3. Nuts with dark, crescent-shaped excavation near blossom end.

   BLACK WALNUT CURCULIO

A. EXPANDING BUDS DAMAGED, EARLY SPRING

1. Bud or expanding leaflets partially eaten; bud and elongating shoot solid, not hollowed out; insects rarely seen feeding.

   MAY BEETLES

2. Buds or expanding leaflets contain small holes; a small pile of insect droppings often present near hole; bud or shoot hollowed out; may contain drab, olive-green caterpillar with black head.

   WALNUT SHOOT MOTH

1. Small, black, trumpet-shaped case attached to leaf stem; may contain drab, olive-green caterpillar with black head.

   PECAN LEAF CASEBEARER

1. Long, jagged scars, up to several inches long, on Aarger twigs; shredded wood fibers may be visible and hanging from scars; large red-eyed insects may be present on trees.

   CICADAS

2. Small 1/8-inch oval slits or depressions in bark of smaller twigs; small brown insects with two cream-colored spots behind a forward projecting hump may be present; insects capable of jumping.

   TWO-MARKED TREEHOPPERS

3. Zipper-like slits up to 1 inch long in bark of smaller twigs; no shredded wood fibers visible.

   PLANT HOPPERS

1. Main branches, especially main stem, broken and usually hanging.

   BIRDS

2. Buds and young twigs nipped off; completely missing.

   DEER

A. BARK REMOVED OR HANGING IN SHREDS ON STEMS OF YOUNG TREES

1. Bark hanging in shreds; no "teeth marks" on exposed wood.

   DEER RUB

2. Bark not hanging in shreds; exposed wood is rough with "teeth marks".

   RODENT DAMAGE
   (e.g. rabbits, mice, squirrels)

1. Pinholes about 1/32 inch in diameter usually found in darkened, dead areas of lower trunk; may also be found in small twigs or branches; often associated with Fusarium canker.

   AMBROSIA BEETLES

2. Holes larger, about 3/16 inch in diameter; not,found in dead areas of trunk; usually form a partial to complete circle around upper trunk near branches.

   BIRDPECK

1. Cracks in bark depressed or flattened and darkened in areas.
   1. Usually evident near groundline on small diameter trees; tree normally dying back to depression then resprouting below dead area.

      FUSARIUM CANKER

   2. Evident around wounds or branch stubs on trees of all sizes, later developing target-shaped areas in wood; affected area enlarging each year.

      NECTRIA CANKER

2. Cracks or openings not depressed, exposing hollow areas or unsound wood; fruiting bodies may be extruding from the tree.

   DECAY

3. Bark peeling away; large tunnels in wood and bark, filled with sawdust; white, legless larvae with broad flat heads present beneath bark and in tunnels.

   FLAT-HEADED APPLE TREE BORER

DIEBACK