Invasive plants to be sprayed on Moloka'i

By Timothy Hurley
Advertiser Maui County Bureau

People fighting invasive species on Moloka'i are planning their first aerial herbicide-spraying operation next month in an effort to control the spread of cat's claw, a thorny shrub that threatens pastures and native forests.

Tina Lau, coordinator of the Moloka'i subcommittee of the Maui Invasive Species Committee, said Caesalpinia decapetala is widespread on O'ahu, Kaua'i and the Big Island, but found only in three relatively small areas of central Moloka'i.

"We think we have a good chance at success," Lau said.

Introduced as a fence plant on ranches before 1910, cat's claw is an aggressive native of tropical Asia, a legume in the pea family. It is a woody, climbing shrub with yellow flowers, and sharp, curvy thorns that grab onto clothing and skin like a fishhook. It climbs on other plants, smothers them and then forms an impenetrable thicket. On Kaua'i, a dead cow was found tangled in a patch of the shrubs.

Lau said cat's claw can also engulf waterways and utility rights of way.

Moloka'i's invasive species committee, nicknamed Mo-ÊMisc, was formed two years ago under the Maui committee to prevent new pests from becoming established on the island. Partners include The Nature Conservancy and the state Department of Land and Natural Resources.

The problem of invasive species isn't as pressing on Moloka'i as on most other islands, and that fact places MoMisc in a strategic position to beat back the kinds of pests now being battled on other islands, Lau said.

Since the committee formed, it has controlled populations of pampas grass, giant reed and New Zealand flax. Miconia and coqui frogs are not known to exist on the island.

As for cat's claw, Lau said areas of growth accessible to people on foot have been controlled with herbicide and hand-pulling. The plan now is to attack the large, dense thickets growing in steep gulches with helicopter spot-spraying of Garlon 4, the same herbicide used to fight miconia.

The first operation, a test run, is scheduled from 7 a.m. to 3 p.m. April 15 in Waiakala'e gulch near Kala'e. If it rains, the operation will be held the next day.

Some of the cat's claw is on private land, Lau said, and permission to use the herbicide was obtained from landowners.

Contact Timothy Hurley at thurley@honoluluadvertiser.com or (808) 244-4880.