It is well known that moths can be an occasional nuisance within and around a home, but they are not widely known as being harmful to humans. Unfortunately, many species of moth larvae (caterpillars) possess venomous urticating hair-fibers, including many tussock moth species.

There exists numerous species of tussock moth-caterpillar, most of which belong to the Erebidae family. Although these caterpillars are well distributed throughout the US, they are particularly well known in the northeast where they inflict millions of dollars in damage to trees located in urban and forested areas each year. Most people living in the northeast have learned that tussock moth caterpillars can also be dangerous due to the venomous hair-fibers that protrude like spikes from their body.

Upon being touched, or after falling onto a human from a tree, a tussock moth-caterpillar’s fibers detach and remain pricked into skin, allowing venom to flow continuously into the bloodstream. Most media sources that discuss the dangers posed by these caterpillars only make mention of one or two species, most commonly the hickory tussock caterpillar and the white-marked tussock caterpillar. However, the northeast is home to a wide variety of tussock moth-caterpillars, some of which are responsible for serious envenomations, while others are more notable as garden or yard pests.

The Sycamore tussock caterpillar species, Halysidota harrisii, is a common defoliating pest to trees in forested, urban and residential settings, but this species’ venom is not as potent as the venom produced by other tussock species. Making contact with this species’ hair-fibers will certainly cause irritation, and perhaps, a minor rash, but serious envenomations by this species have not been documented. The Sycamore tussock caterpillar looks identical to the banded tussock caterpillar species, (Halysidota tessellaris), but the latter species’ habitat is mostly limited to forested areas where they do not pose a threat to residents. Both of these species possess white or light-brown-colored hairs with orange tufts behind their heads, making them easy to spot.

The milkweed tussock caterpillar, Euchaetes egle, is one of the most abundant tussock caterpillars in residential and urban regions, and they are notorious for causing significant damage and death to a variety of tree species. Luckily, this particular species is not widely documented as a medical threat to humans, but they should be removed from yards and gardens due to their destructive habits. This species is easily recognizable for its bright orange, black and red-colored hair fibers. The bright white hickory tussock caterpillar is recognized as the most medically significant caterpillar in the tussock family, but there is some debate among experts concerning this species’ status as a public health threat.

Have you ever been stung by a caterpillar species that you believe was a tussock species?