Watch out for this tree eating bug

If you see brownish-yellow or red discoloration of trees while exploring the Santa Fe National Forest, it may be the result of defoliation from the Douglas-fir tussock moth (DFTM). 

Don’t pick up this cute - and potentially dangerous - caterpillar! The caterpillars have thousands of tiny hairs covering their bodies. The female moths, egg masses, and cocoons also have hairs, which can cause tussockosis, an allergic reaction from direct skin contact with the insects themselves or their airborne hairs. Symptoms may include itchiness, skin rashes, skin irritation, watery eyes, runny nose, and sneezing. More severe reactions, though less common, include blisters, coughing, shortness of breath, wheezing, and chest tightness. Tussockosis severity may vary between individuals, by the amount of exposure, and the level of the outbreak. If contact does occur, immediately wash the area of exposure. If symptoms become severe or problematic, immediately seek medical care. 

Trees may appear to be dying, but those brown branches signal the outbreak of the Douglas-fir tussock moth, a native defoliator whose larvae (caterpillars) feed on the needles of a variety of fir tree species. The caterpillar’s appetite can result in partial or complete defoliation, resulting in tree mortality or vulnerability to bark beetles. 

Last year, caterpillars were found in parts of the Carson, Santa Fe, and Cibola National Forests. Inspections will be carried out in the coming months to monitor the level of defoliation affecting Douglas-fir and white fir trees throughout the forest. An aerial survey will also be conducted to pinpoint specific locations and assess the acreage of the defoliation. Practices aimed at promoting and maintaining a healthy forest—such as thinning dense stands and encouraging tree age and species diversity create the optimal conditions to reduce outbreaks of Douglas-fir tussock moth (DFTM). 

We need your help! If you see these caterpillars, leave them on the ground and report the sighting to your nearest Santa Fe National Forest district office. For updates visit the SFNF website and SFNF social media (Facebook and X). 

About the Forest Service: The USDA Forest Service has for more than 100 years brought people and communities together to answer the call of conservation. Grounded in world-class science and technology– and rooted in communities–the Forest Service connects people to nature and to each other. The Forest Service cares for shared natural resources in ways that promote lasting economic, ecological, and social vitality. The agency manages 193 million acres of public land, provides assistance to state and private landowners, maintains the largest wildland fire and forestry research organizations in the world. The Forest Service also has either a direct or indirect role in stewardship of about 900 million forested acres within the U.S., of which over 130 million acres are urban forests where most Americans live. 

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