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

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

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  • Spiny elm caterpillar 1
  • Spiny elm caterpillar 2
  • Spiny elm caterpillar 3

Spiny elm caterpillar
Nymphalis antiopa

  • Larvae feed in groups, eating leaves; they can defoliate entire branches
  • Mostly black with scattered white spots and a single row of red spots and black spines along its body
  • Larvae feed in May and June and again in July or August by a second generation
  • Turn into mourning cloak butterflies
  • More information on Spiny elm caterpillar
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  • Imported willow leaf beetle 1
  • Imported willow leaf beetle 2
  • Imported willow leaf beetle 3

Imported willow leaf beetle
Plagiodera versicolora

  • Adult beetles make notches or holes in leaves
  • Larvae windowpane leaves, i.e. they feed on the upper surface of the leaves between the veins
  • Prefers willows and poplars, especially weeping willow
  • Adults are bluish-black to greenish blue, about ⅛ – ¼ inch long
  • Larvae are dark, almost black and about ¼ inch long
  • Yellow eggs on underside of leaves in May
  • More information on Imported willow leaf beetle
3 of 8
  • Cottonwood leaf beetle 1
  • Cottonwood leaf beetle 2
  • Cottonwood leaf beetle 3

Cottonwood leaf beetle
Chrysomela scripta

  • Adults eat holes in leaves and along the margins
  • Larvae windowpane feed, i. e. feed on the leaf surface between the veins
  • Prefers willows, cottonwoods and other poplars
  • Adults are ¼ inch long with yellow and black stripes
  • Larvae are black with 2 white dots on either side
  • More information on Cottonwood leaf beetle
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  • Forest tent caterpillar 1
  • Forest tent caterpillar 2
  • Forest tent caterpillar 3

Forest tent caterpillar
Malacosoma disstria

  • Chews entire sections of leaves, often leaving some major veins; defoliation can be severe
  • Hairs along sides of body, blue and black with characteristic footprint shaped white markings on top of body, almost 2 inches long when fully grown
  • Occurs in May and June
  • More information on Forest tent caterpillar
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  • Willow sawfly 1
  • Willow sawfly 2
  • Willow sawfly 3

Willow sawfly
Nematus ventralis

  • Larvae feed gregariously (in nonsocial groups)
  • Young larvae feed on leaf edges and consume entire leaves as they get older
  • Larvae are greenish black to black with black head and large yellow spots on sides; grow to ¾ inch long
  • Two generations per year feeding in May and June and again July to September
  • More information on Willow sawfly
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  • Elm sawfly 1
  • Elm sawfly 2
  • Elm sawfly 3

Elm sawfly
Cimbex americana

  • Larvae chew on leaf edges and consume entire leaves as they get older
  • Full-grown larva has a wrinkled, 2 inch long body; it is pale yellowish to greenish with black stripe down its back with many small white spots
  • Larvae present in June and feed until late July or August
  • More information on Elm sawfly
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  • Japanese beetle 1
  • Japanese beetle 2
  • Japanese beetle 3

Japanese beetle
Popillia japonica

  • Skeletonizes leaves, i.e. chews leaf tissue between the veins creating a lacelike appearance
  • Attacks are common in sunny locations starting at the top of the tree and working down as they feed
  • Adults are a metallic green; bronze wings; 5 white tufts of "hair" along their sides and two white tufts on the tip of abdomen
  • Beetles present from late June through September
  • More information on Japanese beetle
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  • Gypsy moth 1
  • Gypsy moth 2
  • Gypsy moth 3

Gypsy moth
Lymantria dispar

  • Chew leaves and can defoliate trees
  • Mature larvae are 2 inches long; upper side has five pairs of blue dots near front of body followed by six pairs of red dots down the back
  • Damage occurs in June and July
  • Is currently a federally quarantined pest in Minnesota; not established in Minnesota; if found, contact Arrest the Pest: 1-888-545-6684 or
  • More information on Gypsy moth

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