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Extension > Garden > Diagnose a problem > What's wrong with my plant? > Deciduous Trees > Prunus > Holes in leaves or parts of leaves missing

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Prunus > Leaves > Holes in leaves or parts of leaves missing

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  • Image: Eastern tent caterpillar 1
  • Image: Eastern tent caterpillar 2
  • Image: Eastern tent caterpillar 3

Eastern tent caterpillar
Malacosoma americanum

  • Larvae form webs at branch forks, congregating in web only to feed on young leaves
  • In high populations, tree is covered in webbing and defoliated
  • White stripe running length of black body with bright blue spots; almost 2 inches long
  • Damage occurs in May and June
  • More information on Eastern tent caterpillar
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  • Image: Fall webworm 1
  • Image: Fall webworm 2
  • Image: Fall webworm 3

Fall webworm
Hyphantria cunea

  • Chews entire sections of leaves, leaving major veins and can defoliate trees in high infestations
  • Produces silken webbing that covers the ends of branches; silken tent filled with frass and leaf segments
  • Yellowish or greenish with long, fine white hairs with two rows of black spots down its back; approximately 1" when fully grown
  • Damage occurs from late July through September
  • More information on Fall webworm
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  • Image: Japanese beetle 1
  • Image: Japanese beetle 2
  • Image: Japanese beetle 3

Japanese beetle
Popillia japonica

  • Skeletonizes leaves, i.e. chews leaf tissue between the veins creating a lacelike appearance
  • Adults are metallic green; bronze wings; white tufts of "hair" along their sides
  • Beetles present as early as late June and active through September
  • Feeds on 100's of different plant species, including gray birch
  • More information on Japanese beetle
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  • Image: Uglynest caterpillar 1
  • Image: Uglynest caterpillar 2
  • Image: Uglynest caterpillar 3

Uglynest caterpillar
Archips cerasivorana

  • Larvae eat leaves and can defoliate branches
  • Spin webs that become filled with frass and leaf pieces
  • Up to 1 inch long; black head and yellowish to dark green body
  • Cherry trees are preferred hosts
  • More information on Uglynest caterpillar
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  • Image: Leaf spot 1
  • Image: Leaf spot 2

Leaf spot
Blumeriella jaapii

  • Purple to reddish brown spots that are up to 1/10th inch diameter
  • Spots grow together, causing large parts of the leaf to turn brown
  • Leaves with multiple spots turn yellow and fall off prematurely
  • Leaf spots dry up and fall out, leaving holes in the leaf, leave appear to have shot holes
  • Damage first seen in late spring, early summer
  • More information on Leaf spot
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  • Image: Bacterial spot and canker 1
  • Image: Bacterial spot and canker 2
  • Image: Bacterial spot and canker 3

Bacterial spot and canker
Pseudomonas syringae pv. syringae

  • Angular, brown to black leaf spots that eventually drop out leaving holes and giving a ragged appearance on leaves
  • Blossoms turn brown, especially after frost damage
  • Sunken dark colored elliptical cankers form on branches
  • Sticky gums (gummosis) or sour-smelling liquid are excreted from infected branches
  • More information on Bacterial spot and canker

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