When it comes to insect pests, most people are concerned with preventing infestations within their homes, but there exists several insect pest species that establish extensive and destructive infestations in gardens as well. Squash bugs, for example, are some of the most damaging insect pests in gardens, but they do most of their damage to vegetable gardens rather than flower gardens. Aphids damage, and occasionally kill, ornamental plants by using their long piercing beaks to suck nectar from stems, and several species feed on buds and roots as well. Weevils do not infest backyard gardens as often as the insects mentioned above, but if large populations reach residential yards, they will quickly establish a stubborn infestation that often destroys entire gardens. While these insect pests can inflict costly damage to gardens, they are not known for causing human injury with bites or stings. However, the garden pests known as “blister beetles” will not just damage your garden plants, but they will also spray a toxic substance onto your skin that literally destroys tissue.

Blister beetles are abundant in backyard gardens throughout the northeastern states, and rather than biting or stinging humans, these insects secrete a toxic compound known as “cantharidin.” Cantharidin is often referred to as a powerful “blistering agent,” but human exposure to cantharidin can do harm that goes well beyond painful tissue damage. Cantharidin is so effective at destroying tissue that the compound is sometimes used to remove warts. It is not uncommon for horses and livestock to consume blister beetles that are present within the vegetation and hay that they consume. This results in a medical condition known as “cantharidin toxicosis,” and humans have also fallen victim to this condition. Young children playing outside have placed blister beetles within their mouths, causing severe oral tissue damage and acute organ damage when swallowed. Gardeners have developed lasting blisters after being exposed to blister beetle secretions while gardening. Cantharidin secreted by blister beetles has also caused severe and lasting ocular damage after the secretions made contact with eyes. Fatalities resulting from blister beetle ingestion have been documented. The striped blister beetle, the black blister beetle, the margined blister beetles, and the oil beetle are the most commonly encountered blister beetle species in the northeast, and all of these species are known to cause human injury. Wearing gloves that can effectively block fluid absorption is recommended while gardening in order to avoid exposure to blister beetle secretions.

Have you ever encountered a blister beetle within your garden or backyard?