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Watch the release of wasps to help Stinging Nettle Caterpillar control the stinging nettle caterpillar in Hawai‘i! Scan with a QR code smart- phone app or visit: Report any new infestations of stinging nettle http://www.bigislandvideonews.com/2010/06/17/video-wasp- caterpillar in areas other than Hilo and Puna released-to-help-stinging-caterpillar-fight/ Video: David Corrigan Stinging Nettle to the State Pest Hotline, 643-PEST (643- 7378), or contact the Hawai‘i Department Report new infestations in areas other than Hilo and of Agriculture (see the back panel of this Puna districts to the State Pest Hotline: 643-PEST Caterpillar (643-7378) brochure for the branch nearest you).

For more information, contact: Darna pallivitta Hawai‘i Department of Agriculture Hilo: (16 E. Lanikaula St.) 974-4146 What to do if you are stung (or UH-CTAHR, 875 Komohana St., 981-5199) Kahului: (635 Mua St.) 873-3962 • Avoid further contact with the caterpillar’s spines. Honolulu: (1428 S. King St.) 973-9525 • Wash the area immediately with soap and water Lïhu‘e: (4398 Pua Loke St.) 274-3072 to reduce initial pain. • An oral antihistamine may stop itching and Authors swelling. Stacey Chun, Arnold Hara,Ruth Niino-DuPonte Darna pallivitta • Hydrocortisone cream may also stop itching and UH-CTAHR Komohana Research and Extension swelling. Complex, Hilo The stinging nettle caterpillar is of major • Get medical attention immediately if you 1 2 experience difficulty breathing or are stung Walter Nagamine, Patrick Conant, concern because of its painful sting, vor- 2 in the eye. Clyde Hirayama acious appetite, lengthy larval feeding stage Hawai‘i Department of Agriculture, Plant Pest Control • Skin reactions vary from a red welt to severe Branch, 1Honolulu, 2Hilo. (2 months), high fecundity (480 eggs per female), swelling lasting a couple of days. and wide host range. A heavy infestation can Photos of larva and predator wasps by W. Nagamine; other photos defoliate a potted plant in just a few days. by S. Chun and A. Hara.

Caution: Pesticide use is governed by state and federal regulations. Read the pesticide label to ensure that the intended use is included tinging nettle caterpillar was first discovered in on it, and follow all label directions. Hawai‘i in September 2001, at a foliage nursery in Pana‘ewa on the island of Hawai‘i. Nursery References Cock, M.J.W., H.C.J. Godfray, and J.D. Holloway (eds). 1987. Slug PEST workersS there experienced an unusual burning and and nettle caterpillars. CAB International, Wallingford, UK. itching sensation on their skin after handling rhapis Conant P., A.H. Hara, L.M.Nakahara, R.A. Heu. Nettle caterpillar. ALERT palms. Specimens sent to the Smithsonian Institution New Pest Advisory no. 01-03, March 2002 (revision). Hawai‘i were identified as Darna pallivitta Moore. The insect Department of Agriculture. probably arrived from Taiwan and is also found in The caterpillar’s spiny Nagamine, W.T. and M.E. Epstein. 2007. Chronicles of Darna China, Thailand, Malaysia, and Indonesia. hairs release an irritant pallivitta (Moore 1887) (Lepidoptera: Limacodidae): biology on contact and larval morphology of a new pest in Hawaii. The Pan-Pacific Currently, nettle caterpillar infestations have been Entomologist 83(2): 120-135. reported from Volcano to Ninole in East Hawai‘i, with most of lower Puna and nearly all of south Hilo district College of Tropical Agriculture having infestations. In West Hawai‘i, D. pallivitta has and Human Resources been detected in Kailua-Kona, Ke‘ähole, Ka‘üpülehu, University of Hawai‘i at Mänoa and Köhala. Infestations on O‘ahu include central Harm to humans O‘ahu (Mililani, Mililani Mauka, Waipi‘o-Gentry, The nettle caterpillar’s stinging, spiny hairs have a physical Published by the College of Tropical Agriculture and Human Resources (CTAHR) and ä issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, Waikele), Makakilo, and Waim nalo. On Maui, infested effect on human skin similar to that of fiberglass. In addition, in cooperation with the U.S. Department of Agriculture. Andrew G. Hashimoto, Director/ ü ä Dean, Cooperative Extension Service/CTAHR, University of Hawai‘i at Mänoa, Honolulu, areas include Ha‘ik , P ‘ia, Makawao, Wailuku, and the spines release an irritant (a mixture of histamines) Hawai‘i 96822. An equal opportunity/affirmative action institution providing programs and Kïhei. During 2010, the nettle caterpillar was detected produced by a poison gland. The irritant causes the skin to services to the people of Hawai‘i without regard to race, sex, age, religion, color, national College of Tropical Agriculture origin, ancestry, disability, marital status, arrest and court record, sexual orientation, or and Human Resources on Kaua‘i (Lïhu‘e, Kapa‘a, and Kïlauea areas), but has burn and itch. If spines get into the eyes, the irritation can status as a covered veteran. CTAHR publications can be found on the Web site . Publication IP-22, Sept. 2005. Revised July 2011. University of Hawai‘i at Mänoa yet to be recorded on Moloka‘i or L na‘i. be acute; seek medical attention quickly. Identifying and Managing Stinging Nettle Caterpillars

Host Plants LIfe Cycle Control Methods Life cycle Cultural control In Hawai‘i, the nettle caterpillar has been found on more The nettle caterpillar’s life span from egg to adult is 75–99 than 30 plants including palms, pasture and ornamental days, depending on the number of larval stages (instars), Control weeds and modify landscape plantings to limit grasses, weeds, and foliage plants. The nursery industry which ranges from 8 to 11 (45–72 days total). Adult caterpillar food availability. To avoid transporting the has a very low tolerance for the nettle caterpillar—any female and male moths live for approximately 10 and 11 eggs, which are difficult to detect, to new areas, don’t feeding by the larvae significantly damages and reduces days, respectively. As the larvae develop over the 7-day bring in known host plants from any infested area. Ti the value of ornamental and landscape plants. Many of incubation period, the C-shaped embryos are clearly leaf, mondograss and related Liriope groundcover, and the host plants are of high economic value for export and visible. When the larvae are ready to pupate, they migrate palms are preferred host plants of nettle caterpillar. Peak are common in residential and commercial landscaping. toward the base of the host plant to find protected crevices caterpillar populations occur in late summer, so trim these The pest has been observed to complete its life cycle Eggs Incubating Newly hatched An early larva host plants before then and avoid contact during that time. in dried leaves and overlapping plant parts, and they often larvae larvae on a quarter on palms, including areca, fishtail, manila, rhapis, phoenix, pupate in clusters. The larva’s underside darkens to orange and coconut; it also reproduces on dracaena (cultivars Chemical control just before pupation. The prepupa spins brown silk around Some pesticides (pyrethroid, organophosphate, car- ‘Lisa,’ ‘Compacta,’ and ‘Massangeana’) and on starfruit, itself, eventually forming a hardened outer shell. The round ti, iris, coffee, honohono grass, the beach pea (indigenous 5 bamate, and microbial types including Bacillus thur- cocoons are ⁄8 inch (16 mm) long, and pupation occurs ingiensis, or Bt) are effective against the larval stage of Vigna marina), and the endemic mamaki. within the cocoon after 5 days. The caterpillar has been observed feeding (but not re- the nettle caterpillar. Consult a UH-CTAHR Cooperative producing) on many other plants, including bamboo orchid, Eggs Extension Service agent or an agricultural products banana, ‘Pink Quill’ bromeliad, chickweed, Chinese star The female adult moth deposits eggs in small clusters, a professional for help in choosing an insecticide. Fully developed larva, Prepupa Pupa jasmine, cigar plant, rabbitsfoot fern, gardenia, glory bush line, or singly, usually on the undersides of older leaves. 1 about 1 inch long Biological control (Tibouchina), ‘Golden Glory’ perennial peanut, california- Eggs are flattened, transparent ovals, ⁄32 inch (0.8 mm) 1 HDOA staff discovered a locally established tricho- grass, hilograss, mondograss, napiergrass, vaseygrass, wide and ⁄16 inch (1.6 mm) long, appearing as a glassy wainakugrass, guava, Koster’s curse, macadamia, maunaloa sheen on the leaf surface that can easily be overlooked. grammatid wasp depositing its eggs into D. pallivitta eggs, vine, monstera, ponytail palm, red and shampoo gingers, which provide a food source for the wasp larvae, which sleeping grass, Spanish clover (silverleaf desmodium), Larva eventually emerge as adults. This wasp, however, has had walking iris, wedelia, whaleback, and the endemics maile The larva can be up to 1 inch (25 mm) long and is covered only limited effect on the nettle caterpillar population on Hawai‘i. Therefore, HDOA has worked with researchers and wiliwili (data gathered by UH-CTAHR and HDOA). with many rows of stinging spines. Larvae vary from white to light gray, with a dark longitudinal stripe down the back. in Indonesia and Taiwan to identify other biological control Prepupa, pupa agents of D. pallivitta. Smaller larvae cause Larvae begin feeding 2 days after hatching. Onset of Adult moth damage by feeding on the Larvae of a wasp (Aroplectrus pupation depends on food availability and environmental leaf surface, creating a conditions. The pupal period ranges from 17 to 21 days. dimerus) from Taiwan feed and “windowpane” effect. develop on the nettle caterpillar, killing it. These wasps were eval- Adult uated and found safe for Trichogrammatid The adult moth is approx- release in Hawai‘i, and they imately ½ inch (12.7 mm) are now established on several long. The forewing is divided islands. A naturally occurring by a white diagonal marking, cytoplasmic polyhedrosis virus with the upper portion rust- found infecting D. pallivitta colored and the lower portion larvae helps control heavy lighter brown; the hind wings infestations. Aroplectrus are uniform light brown. Adults, resting These nocturnal moths have Physical control not been observed feeding. The adult moth is instinctively attracted to light, so Mating begins about two minimize outdoor lighting at night and use bug-zappers days after emergence. During with ultraviolet bulbs to reduce the numbers of this pest. the day they are inactive Position the unit away from any potential host plants and and retreat into vegetation, under protected eaves, and place a bucket of soapy water Damage by feeding of large larvae on (clockwise from upper Larvae often pupate in clusters in sheltered spots at the usually in an upside-down, directly beneath it to capture fallen moths. left) rhapis, coconut, dracaena, mondograss, and ti. base of the host plant. perching position. Male Female