Slug moth caterpillars, often called “slug caterpillars,” are understudied caterpillar species that are not well defined taxonomically. The first published research on slug caterpillars is more than 100 years old, and this dated source remains the only competent description of slug moth species and their larvae that have been published. Several caterpillar species are commonly referred to as “slug caterpillars,” but early literature on these insects state that slug caterpillars belong to the Limacodidae family. Although slug caterpillars are in need of greater academic attention, many species are known to be economically significant pests within the northeastern states, as numerous slug caterpillars inflict damage to tree and plant species in the region. Many slug caterpillars are also medically significant pests that are well known for inflicting painful stings to humans that can trigger allergic reactions in rare cases.
Many slug caterpillars are quite small and flat-bodied, and much like slugs, some species are able to crawl on the underside of leaves. While slug caterpillar research dates back more than a century, slug caterpillar species are described as a public health threat in many medical texts due to the venomous spines that protrude from their bodies. Unsurprisingly, it is not uncommon for gardeners to sustain stings from slug caterpillars. Around 50 slug caterpillars can be found in North America, and nearly all of these species inhabit forested areas in the northeast where they inflict damage to trees. These slugs also infest trees and gardens in residential lawns and urban parks. One pest species in New York, the pin-striped slug caterpillar, has only been documented as inhabiting Long Island, and while this species’ natural habitat is rapidly being lost to urban expansion, they can likely be found in many other areas of the state. This species infests pine trees and is known to possess venomous spines. The most well known slug caterpillar that feeds on trees and garden plants in New York is often called the spiny oak slug caterpillar (Euclea delphinii), and specimens can be spotted on oak, beech, chestnut, willow, pear, bayberry, sourwood, wild cherry and many other tree species. This slug caterillar’s urticating hairs frequently remain stuck in the skin, causing a painful sensation that is comparable to a bee sting, but these caterpillars are not dangerous. Slug caterpillar infestations in residential trees and gardens can be controlled with bacterial sprays.
Do you believe that you have spotted a slug caterpillar in your yard?