Cankerworm Tree Insect


The tender leaves of a wide variety of tree species are food for fall and spring cankerworms, leaf-chewing caterpillars. Elm, oak and apple are favorites; however, cankerworms attack many other hardwoods including: 

  • Maple 
  • Linden
  • Beech
  • Cherry 
  • Hickory 
  • Ash 

What are the symptoms of a cankerworm infestion?

Chewed and ragged leaves are unsightly as damage occurs suddenly in late April through mid-May. However, most concerning is the stress brought on by leaf loss at a time when leaves are essential for nutrients for tree growth. 

What do cankerworms look like?

Caterpillars vary in color from green to black. When full-grown, they are approximately one inch long. Because of their small size, the pests are easily blown from tree to tree and property to property. 

Treatment and Management Options

Cankerworm populations can be reduced so that less feeding occurs, thereby helping to protect the health of your trees. A pesticide treatment for affected trees is recommended. Fertilization of trees with leaf loss is also recommended.

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