Beware of oak caterpillars April to June

Oak processionary moth larva

By USAG Stuttgart Directorate of Public Works
Operations & Maintenance Division

Updated June 8

The Oak Processionary Caterpillar is a moth that can be an irritant to human skin. The most dangerous months annually are April to June. To avoid them, keep away from oak trees which are infected by caterpillars. Park oaks or free standing trees are more often infected. Indicators are white-grey weave nests and large groups of caterpillars at the trunk of the tree.

A native species of the Mediterranean region, this caterpillar is well established in the Stuttgart region. Oak trees at the edge of a forest can be infested, as well as a single oak tree at a garrison housing area, park or playground.

The caterpillars typically follow one another head-to-tail in long “processions” to and from the nest, and from one feeding position to another. The caterpillars are covered in tiny hairs that can cause itchy and painful rashes if they come into contact with skin. Contact with these hairs can irritate one’s lungs, eyes and skin, and in some cases, can cause severe allergic reactions.

What you can do:

  • Don’t touch caterpillars or nests.
  • In case of contact with the caterpillar’s hair, take a shower promptly and wash clothing.
  • Keep windows closed if you live near infected oak trees.
  • Seek medical attention in the event of severe exposure.
  • Wear long-sleeved clothing in wooded areas.

Call the O&M Division, Pest Management Coordinator, at 431 -2855, if you have questions.

Area caterpillars could cause rash