Archive:Poplar/How to Use the Key
From Bugwoodwiki
From: Ostry, Michael E.; Wilson, Louis F.; McNabb, Harold S., Jr.; Moore, Lincoln M. 1988. A guide to insect, disease, and animal pests of poplars. Agric. Handb. 677. Washington, DC: U.S. Department of Agriculture. 118 p.
I.Carefully examine the injury, noting any major symptoms or signs.
II.Look under the appropriate headings in the key for the part of the tree and type of injury you are trying to identify.
III.Compare the descriptions and illustrations with your observations. Identification Key to Major Insects and Disease of Poplars
I. Injury to Cuttings or Seedlings
A. Failure of unrooted hardwood cuttings to flush or shoots quickly die.
1. Cuttings shriveled, blackened, with "pimple-like" structures on surface.
B. Shoots severed at soil surface.
1. Cuttings not blackened.
II. Injury to Foliage
A. Leaves eaten.
1. Webbing present on branches.
a. Large webs (up to 3 feet in diameter).
b. Small-large bags or tents.
2. No webbing present
B. Leaves not eaten.
1. Young leaves withered, may droop, later turn black. a. Generally present throughout trees in planting, no necrotic blotches on adjacent leaves.
b. Scattered or more prevalent on groups of trees, necrotic blotches on leaves.
2. Leaves with large, irregular blotches, with or without concentric rings, usually not limited by veins. a. Large areas of leaves turn light brown in early summer, later dark brown-black "ink spots" develop within affected area.
b. Leaves in lower crown have brown-gray blotches and white concentric rings.
c. Leaves with brown to whitish-gray blotches and small black dots (fruit bodies) within.
Phyllosticta leaf blotch.
d. Leaves with patches of white-gray powder.
e. Leaves distorted, skeletonized.
f. Leaves with blisters, galls, or mined areas of various sizes and shapes.
3. Leaves with small spots, often later coalescing into small, irregular blotches, generally limited by veins.
a. Circular spots reddish with a chlorotic halo early in season, later turning dark brown, often with a whitish raised center. Undersides of severely affected leaves bronze in color.
b. Spots generally larger and more angular than above, occasionally irregularly shaped tan blotch bordered by a dark brown margin.
c. Yellow-orange spots, later forming an orange powdery mass on undersides of leaves.
4. Leaves misshapen, chlorotic, stunted.
a. Leaves with various mosaic or mottled chlorotic patterns.
b. Leaves stunted, "burned" appearance.
c. Leaves crinkled, missing on terminal shoots. Cottonwood leafcurl mite.
d. Terminal shoots and leaves covered with colonies of aphids.
5. Leaves folded.
6. Leaves tightly rolled.
III. Injury to Shoots
A. Elongating shoots injured in early spring.
1. Shoots curled, leaves wilted, terminals resemble a shepherd's crook.
a. Shoots and leaves black.
b. Shoots and leaves green or black, wilted.
2. Frothy spittlemass on terminals.
3. Shoots swollen, irregular scars along shoots, dead or dying terminals.
4. Large, irregular, green or brown galls on terminals.
B. Terminal shoots missing.
1. Small tree branches and shoots cleanly cut off near ground line.
2. Upper shoots of small trees nipped off, leaving a ragged end.
IV. Injury to Branches and Trunk
A. Bark removed or hanging in shreds on stems.
1. Bark hanging in shreds, no teeth marks on exposed wood.
2. Bark not hanging in shreds, teeth marks on exposed wood.
3. Bark split away, exposing wood at base of tree, usually on the southwest side.
B. Cracks, deformities, dieback, fruit bodies.
1. Depressed, dark central area often with cracks.
2. Yellowish-orange areas, often with many raised pimple-like structures (fruit bodies). Bark usually intact, often rough on older trees.
3. Target-shaped rings of dead bark. Miscellaneous cankers
4. Yellowish-orange to black, slightly depressed areas, blistering bark with gray pegs or gray black cushion-like structures.
5. Hoof-shaped conks along upper stems of pole-size and larger trees.
6. Slime flux originating from a wound or branch stub, running down side of trunk.
7. Tumor-like growth, warty appearance, large galls.
8. Holes in bark with sap, wood shavings, and frass present.
9. Tunneling at base of stem.
a. Sap flow and wood shavings present.
b.Swollen galleries encircling base.
c. Frass in root collar and main roots.
10. Slits on branches up to 3 inches long.
11. White-brown crust on bark surface.
12. Branch and stem swellings.
a. Clumps of green plants present.
b. Scars or holes present on swellings or galls.
13. Root and butt rot.
