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

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Black Walnut > Leaves > Holes in leaves or parts of leaves missing

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  • Image: Walnut caterpillar 1
  • Image: Walnut caterpillar 2
  • Image: Walnut caterpillar 3

Walnut caterpillar
Datana integerrima

  • Young larvae skeletonize the leaf causing a lacelike appearance
  • Mid-sized larvae consume all foliage except for midveins on one branch before moving to another
  • Mature larvae consume all foliage, including the midvein excluding the petiole
  • Larvae up to 2 inches long, yellow stripes running lengthwise on gray to rust red body with long hairs
  • More information on Walnut caterpillar
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  • Image: Yellownecked caterpillar 1
  • Image: Yellownecked caterpillar 2
  • Image: Yellownecked caterpillar 3

Yellownecked caterpillar
Datana minnistra

  • Young larvae feed in groups and skeletonize leaves by eating the leaf tissue and leaving the veins.
  • As larvae mature, they become solitary feeders and eventually eat the entire leaf.
  • Larvae are active from late July through early September.
  • They have black heads with striped body covered with fine white hairs and a bright yellow spot behind the head.
  • More information on Yellownecked caterpillar
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  • Image: Gypsy moth 1
  • Image: Gypsy moth 2
  • Image: Gypsy moth 3

Gypsy moth
Lymantria dispar

  • Chew leaves and can defoliate entire 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 Arrest.the.Pest@state.mn.us
  • More information on Gypsy moth

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