Elm, American/Hybrid
Symptom Cause  
Leaves galled or distorted
Aphids
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Black powdery sooty mold fungus forms on honeydew; branches may die
Aphids
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Swollen lesions on stems and trunk
Bacterial Canker
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Many holes in branches; limbs girdled sawdust at holes
Borers
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Young portions of foliage disappear, or young tips disappear, bark peeled off
Deer
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Leave wilt; branches die
Dutch Elm Disease
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Leaves skeletonized
Elm Leaf Beetles
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Leave curl and wither
Elm Phloem Necrosis (viral)
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Bark of stems and roots gnawed
Rodent Injury
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Branches encrusted with small bumps
Scale Insects
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Holes in bark; bud and twig damage
Smaller European Bark Beetle
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Black powdery sooty mold fungus forms on honeydew; branches may die
Sooty Mold
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Leaves turn yellow or brown and wither
Wilt (fungus)
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