University of Illinois Extension

University of Illinois Extension

Hort Answers

Insect Damage

Zimmerman Pine Moth
Dioryctria zimmermani

3 (1 = rare 5 = annual)
4 (1 = very little damage 5 = plants killed)
Zimmerman pine moth feeds on Scots and Austrian as well as other pines.

Plants Affected

The insect causes the pitch to flow from wounds on the trunk near branch whorls on Scots and Austrian pine. When feeding damage is severe at all the crotches at a particular whorl of branches, the trunk may break off at that whorl. Feeding damage at the base of branches can girdle and kill the branch, even major branches.

On Eastern white pine, this insect is a tip borer, tunneling through new shoots, causing dieback of branch tips.

Life Cycle
Eggs hatch in late summer (August) into caterpillars that wander across the bark, eventually spending the winter under a flap of bark. In the early spring (April) they emerge and wander again across the bark before tunneling through the bark into the trunk or major branches of Scots and Austrian pine. Through the spring and summer, the caterpillar feeds as a borer, pupates, and then emergesas a moth in late summer.

Prune out damaged wood. If necessary use a recommended insecticide. Control may be done in spring when saucer magnolia is in pink bud to early bloom or in mid to late summer when panicle hydrangea is pink.

Related Resources
Home, Yard & Garden Pest Guide
Illinois Commercial Landscape and Turfgrass Pest Management Handbook
U of IL - Distance Diagnosis through Digital Imaging
U of IL - Plant Clinic