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Extension > Garden > Diagnose a problem > What's wrong with my plant? > Deciduous Trees > Elm > Unusual projections on leaves

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Elm > Leaves > Unusual projections on leaves

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  • Image: Elm finger gall 1
  • Image: Elm finger gall 2
  • Image: Elm finger gall 3

Elm finger gall
Eriophyes ulmi

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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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  • Image: Elm casebearer 1
  • Image: Elm casebearer 2

Elm casebearer
Coleophora ulmifoliella

  • Larvae mine angular spots between leaf veins causing brown areas that can coalesce to complete browning in high infestations
  • Create cigar-shaped cases out of leaf tissue and silk that hang from leaf underside
  • Preferred hosts are American, red, and slippery elm
  • More information on Elm casebearer

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