The state Department of Agriculture plans to poison wild honey bees in Hilo as an emergency measure to try to stop a growing infestation of bee-killing varroa mites, and warns the public against eating honey from wild hives over the next three weeks.

The department is using a "crisis exemption" to deploy the insecticide fipronil at about 200 bait stations within a five-mile radius of Hilo Harbor.

Agriculture Department officials have consulted with the U.S. Environmental Protection Agency on the plan for several months and sought the crisis exemption from the EPA after other methods of baiting and manual destruction of feral hives failed to stop the spread of mites.

In recent weeks, an increasing number of bees with varroa mites have been found in test catches within the Hilo area, which officials said means mites are being spread from undetected wild hives.

"The EPA crisis exemption is critical if we have any hope of eradicating varroa mites from Hawai'i Island," said Lyle Wong, administrator of the Agriculture Department's Plant Industry Division. "None of the other methods we have researched and attempted have been successful in ridding the island of this pest."

The Agriculture Department said it will use "very low concentrations" of fipronil, and is following EPA recommendations to minimize impact on other animals and plants. The department also said it has consulted with the U.S. Fish and Wildlife Service to make sure that endangered or threatened species aren't affected.

Warning people not to eat wild honey from the eradication zone is an "extra precaution."

Fipronil is a widely used insecticide approved for many crop and noncrop applications since 1996 in the U.S. One common use is to control fleas and ticks on pets.

The use of the insecticide in the Hilo area will be allowed for 15 days. If more time is needed, the state must apply for a quarantine exemption, under which the location of each bait station will need to be recorded by global positioning system and monitored at least every 24 hours.

Varroa mites, which are a reddish-brown color and spread from hive to hive through bee contact, were first detected in Hawai'i on O'ahu by a beekeeper in April 2007.

The mites were first found on the Big Island last August. Since then, state officials have tested about 373,000 bees from the Hilo area and detected 29 incidents of varroa mites involving 310 individual mites.

Agents have set about 170 swarm traps to capture feral bees, set up more than 150 bait stations and destroyed more than 200 feral hives. No mites have been detected at hives maintained by commercial beekeepers.

The Big Island is home to a queen bee industry that's a major supplier of disease and pest-free queen bees to markets worldwide, generating more than $4 million in sales annually.

If the mites spread and wipe out the state's bee population, costs to farmers would be $42 million to $62 million a year, according to a preliminary Department of Agriculture estimate.

Varroa mites are among the most destructive pests of honey bees, and so could threaten pollination of flowers and food crops statewide.

If you have questions about the eradication plan, call the Agriculture Department in Hilo at 974-4140 or in Honolulu at 973-9530.

More information on varroa mites is available online at http://hawaii.gov/hdoa/pi/ppc/npa-1/npa07-01-Varroa.pdf and http://hawaii.gov/hdoa/pi/ppc/varroa-bee-mite-page.