Plans to eradicate mosquitos at Possession Beach aren’t as simple as previously thought.

The Port District of South Whidbey had planned to apply an aquatic pesticide to a canal and a pond at the Possession Point Park this season, but plans were put on hold by the Island County Health Department this week.

The port was going to use a household product known as Mosquito Dunk to the two stagnant water areas, areas known to be mosquito breeding grounds. The Mosquito Dunks are solid pieces of the bacteria Bacillus thuringiensis israelensis, or Bti, a microbe that attacks and destroys an insect’s digestive tract.

But since no port employee is licensed to use Bti in natural bodies of water, the port will have to delay its mosquito eradication plans.

According to Art Pratt, caretaker at Possession Point, the still water at the park could breed millions of mosquitoes. But the law does not allow him to treat those waters without certification. Mosquito Dunk sold in consumer form is intended for contained waters, such as birdbaths and lined garden ponds. Its use is illegal in natural bodies of water or those that interact with the rest of the environment.

The health department put the brakes on the port’s plans to start killing mosquitoes after a department employee learned of the port’s intended program through a newspaper article.

Kathleen Parvin, an environmental health specialist for the health department, said that because pesticides are so heavily regulated, the port has to obtain a permit and license before moving forward.

“You’ve got to follow the label,” she said.

According to Parvin, the application of aquatic pesticides to natural bodies of water requires federal, state and local permits. Applicators of the pesticides must be specifically licensed by Washington State Department of Agriculture to apply aquatic pesticides.

“People need to understand that pesticides are regulated heavily,” Parvin said.

Using the products without permits is a common mistake. Those using products such as Mosquito Dunk need to read the label to find out what sorts of pesticides are allowable in what sorts of situations.

“B.t.i. cannot be used on items not listed,” she said.

With summer just around the corner and mosquitos on their way, the port will send Pratt to classes in Puyallup in April to become licensed to apply aquatic pesticides.

Parvin said the port will also need to make sure it is using pesticides that are registered with the Environmental Protection Agency to comply with federal rules.