An insect that feeds on pine trees

Zimmerman pine moth is a native pest in the northern half of the United States, east of the Rocky Mountains. Its larvae burrow into pine trees and other conifers and feed tree tissues. The burrowing weakens the infected branches and can cause breakage. A heavy infestation may girdle and kill portions of the tree or even the entire tree.

Infested trees require treatment for control
Scotch, Austrian, Ponderosa, Mugo and occasionally white pine are susceptible to the Zimmerman Pine Moth. Topical treatments with insecticide are required for control. If the tree is showing significant dieback, it is usually too late for control measures.

What to look for
• Oozing globs of resin seeping from the bark of tree.
• Burgundy larvae underneath the resin mass.
• Broken tops or main branches of a tree.

Life Cycle
• Moths emerge from in late August through September.
• Eggs are laid on buds at the ends of branches and around wounds.
• Larvae feed in fall before entering hibernation through winter.
• In April, larvae resume feeding and burrow into bark.
• Resin masses appear by late spring and early summer.

Treatment and Prevention
• Use low nitrogen fertilizer.
• Make sure watering is adequate.
• Trees planted too close together are more susceptible.
• Shaded trees are susceptible.

Treatment timelines are dependent upon your tree, landscape, insect  infestation levels, time of season, and available treatment options.

An adult moth is approximately 5/8 inch long.
Tree and Branch Damage
Zimmerman Pine Moth resin masses.