Big Island fights stinging nettle caterpillar
By Jan TenBruggencate
Advertiser Science Writer
State health officials already trying to cope with a mosquito-borne outbreak of dengue fever now are trying to control a new pest: a stinging caterpillar that has appeared on the Big Island.
Arnold Hara • University of Hawai'i-Hilo
The stinging nettle caterpillar was recently found eating the mature leaves of rhaphis palms at a Pana'ewa nursery.
A stinging nettle caterpillar has been discovered at a Big Island nursery.
It has bristly spines that can pierce skin. The spines contain a compound that causes a burning sensation that lasts about an hour.
It is not known if the creature is dangerous to people who are sensitive to insect stings, said Larry Nakahara, manager of the state Department of Agriculture's Plant Pest Control Branch.
Officials have not positively identified the exact species of nettle caterpillar discovered on the Big Island, and have sent out descriptions and photographs to experts around the world.
It is not clear when or how it arrived.
Workers first noticed it about three weeks ago on rhaphis palms, commonly known as "lady palms," at a Pana'ewa nursery, agriculture officials said. They reported it to state officials a week ago.
The caterpillar is about an inch long, and is white with black bands. It is found mostly on the underside of leaves.
In the pupal stage, it is spherical and looks fuzzy. Nakahara said it is found near the base of plants.
The moth is described as smaller than a dime.
The top two-thirds of the moth is a yellowish brown, and the bottom third is just brown. The adults are active at night and hide under leaves by day.
Nakahara said the nursery sprayed to control the caterpillar, but since then, pupae have matured and moths have appeared. They are also being sprayed with insecticides.
Officials have not found the stinging caterpillar or its moth outside the Pana'ewa area, nor has it been reported on any other island. But they are enlisting the public's help in looking for infestations.
Anyone who finds the insect may call the Plant Pest Control Branch on their island.
Nakahara said that although it has been found only at the one nursery on the Big Island, "it doesn't look like it started at that nursery."
Such infestations often arrive with shipments of plants from abroad.
Nakahara said that although the origin of the stinging nettle caterpillar is not known for certain, "we're thinking it might be Southeast Asian."
The infestation points up a continuing problem in Hawai'i with alien species of all kinds.
The Islands are battling invasive plants such as miconia, animals such as imported snakes and lizards, insects such as the stinging caterpillar, and diseases such as dengue fever.
You can reach Jan TenBruggencate at jant@honoluluadvertiser.com or (808) 245-3074.
