Native Insects and Diseases

Native insects and diseases cause problems, too.

The Forestry Information Center can answer many of your questions. When sending an email please provide contact information (phone number and post office address) and the information you want.

Or, you can send samples to one our labs:

Plant Health Diagnostic Lab
Insect Identification Center
Analytical Services and Soil Lab

Common Pests of NH Trees and Forests


Caliciopsis Pine Canker

A native canker is posing a growing problem for pines across New Hampshire and several other eastern states. Caliciopsis pinea can be found in dense pine stands in sandy and well-drained soils. Signs of possible C. pinea infection include cankerous growths and significant sapping, as well as crown thinning and decreases in crown density.

The Basics

Caliciopsis Canker fact sheet NH Division of Forests and Lands
Firewood Quarantines

Caliciopsis cankers with fruiting bodies

Photo courtesy of Jen Weimer.


White Pine Needle Damage

In recent years, landowners and foresters in the northeast have seen browning of white pine needles in the spring and early summer. Three fungi appear to be the culprits. They include Mycosphaerella dearnessii, Lophophacidium dooksii and Bifusella linearis.

The Basics

Monitoring Eastern White Pine Decline and its Causes
Dramatic Needle Browning and Canopy Dieback of Eastern White Pine (Pinus strobus) in Southern New England UMass Extension, Spring 2016
Eastern White Pine Needle Damage Survey 2011
Firewood Quarantines

White pine needle

Forest Tent Caterpillar

Forest tent caterpillar is a native insect that is a natural part of our ecosystem. At times, as in the summer of 2016, forest tent caterpillars can cause extensive defoliation in hardwood forests. Defoliation can stress trees, but most trees will recover.

We will provide updates on outbreaks as more information becomes available.

The Basics

Tent Caterpillars
Vermont Forest Health--Forest Tent Caterpillar Update June 2016
Recommended Actions Regarding Forest Tent Caterpillar Defoliation on NH Forestlands

forest tent caterpillar on native ash