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Extension > Garden > Diagnose a problem > What's wrong with my plant? > Deciduous Trees > Elm > Leaves are curled or twisted or distorted

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Elm > Leaves > Leaves are curled or twisted or distorted

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  • Image: Woolly Elm Aphid 1
  • Image: Woolly Elm Aphid 2
  • Image: Woolly Elm Aphid 3

Woolly Elm Aphid
Eriosoma americanum, E.lanigerium and E. rileyi

  • Severe infestation can twist and curl leaves; leaves can yellow; branches can dieback
  • Colonies on wood are covered by a white waxy or cottony material
  • Produces honeydew from the aphid feeding, look for sooty mold on leaf surfaces or twigs
  • Adults are dark colored (reddish, brown, purplish), tiny size (1/16 to 5/32 inch)
  • Preferred hosts are American and slippery elm
  • More information on Woolly Elm Aphid...
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  • Image: Elm cockscomb gall aphid 1
  • Image: Elm cockscomb gall aphid 2

Elm cockscomb gall aphid
Colopha ulmicola and C. graminis

  • Aphid induces a 1 inch long by ¼ inch high wrinkled swelling on the leaf surface, irregular like a rooster’s comb
  • Reddish at first but turning brown as the season progresses
  • Found on American and red elm
  • More information on Leaf galls...

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