VM May Ad Tower EZ Secured US 042524

Pest Information

Walnut Caterpillar

Walnut Caterpillar

  • Latin Name: Datana integerrima
  • Common Name: Walnut Caterpillar
  • Other Names: N/A

Pest Details


This is a native species in North America.


This is one of several species of moths in the genus Datana, and it is found throughout eastern North America west to Oklahoma and Texas, and has even been found in Arizona. The larvae restrict their feeding to trees such as walnut, pecan, and hickory, and outbreaks of the caterpillars may result in serious defoliation of the trees and forested areas. The female deposits masses of 120-880 eggs on the undersurface of a leaf. The larvae feed gregariously when young, skeletonizing leaves in small areas of the tree, but as they mature they spread out to consume entire leaves throughout the tree. A single generation occurs in northern regions and two generations may occur in southern states. When a tree is sufficiently defoliated the larvae will drop to the ground and seek out other nearby host trees. When mature the larva falls to the ground to burrow into the soil to pupate, spending the winter in the pupa.


Newly hatched larvae are light green changing to brown as they grow and finally to black as the mature larvae. The body is covered with short (early larvae) to long (mature larvae) white hairs, and narrow white stripes run the length of the body on the top and sides. When disturbed the larva exhibits a defensive posture by suddenly raising the front and rear of its body. The adult moth is large with a wingspan of over 1.5 inches and is a light tan to reddish brown color. Four darker lines run across the forewings from the front edge to the hind edge.

Characteristicts Important to Control:

When discovered early the mass of feeding larvae can be physically removed by pruning off the section of the branch and disposing of it. Where this is not possible or when larvae are feeding generally on the tree a contact insecticide may be applied.

24 SEN 00187 Veseris Banner Ad FNL 5
Back to top