Stinging Nettle Caterpillar

The Cooperative Extension Service of the College of Tropical Agriculture and Human Resources at the University of Hawai‘i at Manoa has posted a brochure on the Stinging Nettle Caterpillar where I got most of my information from.

Stinging Nettle Caterpillar
Scientific Name – Darna pallivitta
First appearance – September 2001, Panae‘wa, Hawai‘i (Foliage Nursery)
Origin – It is believed that the nettle caterpillar arrived from Taiwan. It is also found in China, Thailand, Malaysia, and Indonesia

The nettle caterpillar poses a big threat because of its painful sting, large appetite, lengthy larval feeding stage, high reproduction rate, and wide host range.

Host Plants
The nettle caterpillar has been found on more than 45 different plants in Hawai‘i including but not limited to palms, pasture and ornamental grasses, weeds, and foliage. When the nettle feeds off the host plant it damages and reduces the value of the plant, putting a burden on nursery owners who rely on their plants for export. Originally found in Pana‘ewa near Hilo, the nettle has now spread to Waiakea, Waiakea ‘Uka, Kaumana, Pi‘ihonua, Kea‘au, Kurtistown, Hawaiian Paradise Park and Orchidland.

Life Cycle
The life span of the nettle caterpillar from egg to adult is 75-99 days depending on the number of larval stages. Adult females live for approximately 10 days and adult males live for approximately 11 days. The larvae develop during a seven day incubation period where embryos are visible. When ready to pupate the larvae move to the base of the host plant for protection. The prepupa will spin a brown silk around itself forming a hardened cocoon approximately 5/8 inch long, and pupation occurs with the cocoon after five days. And do we get a beautiful butterfly perhaps? Of course not…the caterpillar turns into a moth. The adult moth is approximately ½ inch long. The adult female deposits eggs in small clusters on the underside of leaves. The adult moths are nocturnal. During the day they are inactive and head for vegetation in an upside-down perched position.

Harm to Humans
The nettle caterpillar has stinging spiny hairs that releases an irritant (mixture of histamines) produced by a poison gland. The irritant causes the skin to burn and itch, much like the effect of fiberglass. If not treated, the site of irritation can become infected. If you are stung you should avoid further contact with the caterpillar, and immediately wash the area with soap and water to calm the pain. Antihistamines or hydrocortisone cream can be used to stop the itching and swelling. If you are stung in the eye or begin having difficulty breathing, seek medical attention immediately. Individuals will have different symptoms depending on the severity of any allergic reaction.

Control Methods
- Minimize outdoor lighting at night
- Use bug zappers with UV bulbs (position zappers away from potential host plants and place a bucket of soapy water underneath to catch fallen moths)
- Don’t bring in host plants from an infected area
- Use of pesticides/insecticides

For more information on the Stinging Nettle Caterpillar visit these websites:
Nettle Caterpillar
Stinging Caterpillar Expanding its Range on the Big Island
Have you seen Stinging Nettle Caterpillar?