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