State agricultural crews have been busy attacking invasive species on Oahu this week, capturing three coqui frogs and taking 1,000 samples from a newly discovered infestation of little fire ants in Waimanalo.

The frogs were captured by state Department of Agriculture crews Wednesday night in separate areas of Oahu one on a boat at a residence in Kahaluu and the others at nurseries in Kaimuki and Kunia.

All three incidents were reported Monday and Tuesday by neighbors of those properties who reported hearing the coqui frog’s loud, distinctive two-tone mating call, officials said.

"Our staff on Oahu have been diligent in following up on calls from the public and have been able to eradicate coqui frogs on this island," Scott Enright, chairman of the Hawaii Board of Agriculture, said in a statement.

It’s suspected that the frogs found at the nurseries hitchhiked from Hawaii island on plant material. The Kahaluu capture involved possible movement aboard a boat that was shipped from Hawaii island, officials said.

Also believed to have made their way here from Hawaii island are the little fire ants, tiny creatures with a big reputation for their painful bite that produces large red welts.

On Thursday state Department of Agriculture employees joined crews with the U.S. Fish and Wildlife Service, University of Hawaii and the Oahu Invasive Species Committee at an ant infestation discovered last week near Waikupanaha Road in Waimanalo.

The samples were taken from a 2,500-square foot area using plastic vials and peanut butter to lure the ants. The vials will be frozen to help preserve the ants for identification.

Officials will assess data found Thursday and come up with a plan for eradication, Enright said.

Enright said Wednesday he’s confident the infestation believed to be at least 2 or 3 years old can be eradicated, but it could take a year or more.

The little fire ant was first detected in Hawaii in the Puna area in 1999. It wasn’t found on Oahu until December, when it was discovered at several nurseries that had received shipments of hapuu logs from a Hawaii island nursery.

Should the little fire ant, or Wasmannia auropunctata, become established on Oahu, it could be a costly problem. The annual impact could reach $170 million in the next few years, according to a recent University of Hawaii study.

On March 27 state investigators seized two dozen frogs from a Manoa home, including four poison dart frogs that were sent to Hawaii through the U.S. mail, according to the Department of Agriculture.

"As with any potential invasive species, we encourage residents to be our eyes and ears and report possible infestations," Enright said.

Suspected invasive species should be reported to the state’s toll-free pest hotline at 643-PEST (7378).