Kealia Pond officials mount effort to cut midge population

By Timothy Hurley
Advertiser Maui County Bureau

KIHEI, Maui — After a two-year reprieve, the pesky, swarming midges at Kealia Pond National Wildlife Refuge are back.

But this time, workers at the sanctuary have a new weapon in their toolbox to help reduce their numbers, and control efforts are scheduled to begin this week.

The recent heavy rains that filled Kealia Pond also brought about a gradual increase in the number of spotted-winged midges, a chronic problem that has plagued neighboring condominium dwellers for the last decade.

Refuge Manager Glynnis Nakai said yesterday that a compound known as s-methoprene, which interferes with the insect's maturing process, will be spread in pellet form across more than 100 acres of open water in the pond.

"Although we won't be able to totally eliminate the midges, we believe we can reduce the nuisance to our neighbors," Nakai said.

Nakai said refuge staff members have been monitoring the midges since mid-December. The small gnat-like creatures swarm at night and at dawn and dusk during winter and early spring. The midges are attracted to light and are tiny enough to fly through window screens, making them a major nuisance to nearby condominium residents who have repeatedly urged the U.S. Fish and Wildlife Service to do something to control the bugs.

Research conducted at the refuge in 2001 pointed to the effectiveness of s-methoprene, Nakai said. The chemical, which is contained in a product called Strike pellets, is an "insect growth inhibitor" that mimics an insect juvenile hormone and prevents the larvae from emerging as adult flying insects, she said.

The chemical is slowly released from the pellets for approximately 21 to 28 days after field application.

Since the spotted-winged midges' life cycle is two to 2 1/2 weeks, one application targets about two generations of midges. With fewer midges emerging as adults, fewer eggs will be produced for the next generation.

The pellets will be applied by a spreader on a boat. The vegetation and edges of the main pond will not be treated to protect endangered and migratory birds, with special attention given to Hawaiian coots that are in different stages of nesting — laying eggs, incubating and some with broods.

Nakai said the larvae and emerging adults will continue to be monitored and, if necessary, the pond will be treated a second time.

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