Two Delaware City Council members aren't happy with the state's plan to disperse pheromones over a portion of the city by plane to prevent the spread of an invasive pest.

Two Delaware City Council members aren't happy with the state's plan to disperse pheromones over a portion of the city by plane to prevent the spread of an invasive pest.

The council voted 5-2 Monday, March 24, to return a letter to the Federal Aviation Administration acknowledging the city received notice of the gypsy moth prevention program. Councilwoman Lisa Keller and Councilman Chris Jones voted against the measure, citing public health concerns.

The Ohio Department of Agriculture has proposed spreading Disrupt II -- plastic flakes containing gypsy moth sex pheromones -- over about 1,700 acres in the city and Delaware Township, with Mingo Park at the center of the treatment area. That treatment, which will occur sometime in June, represents six grams spread over each acre, or about one flake over every three square feet.

"My major concern is when I researched the chemical ... (I) found that 82.1 percent of it is listed as an "other" ingredient," Keller said.

David Adkins, gypsy moth program manager for the department, attended the meeting to address city officials' concerns. He said the 82.1 percent listed as "other" is likely the plastic surrounding the pheromone.

He said the breakdown of the ingredients that go into the plastic is proprietary information that the product's manufacturer does not need to release.

Keller said she was concerned because she could find no studies regarding Disrupt II's long-term effects on humans. Jones said he shared Keller's concerns about the product's ingredients and added that he worried about the ability of pilots to accurately drop the flakes solely on tree canopies.

Adkins said the product's manufacturer, Hercon, had to meet strict federal Food and Drug Administration safety standards before bringingDisrupt II to market.

He said the department of agriculture planned to use theDisrupt II for "a little birth control on the gypsy moth."

According to the Ohio Department of Agriculture, the pheromone flakes mask the pheromone emitted naturally by female gypsy moths and make it harder for them to attract a male for mating purposes.

"Gypsy moth is an invasive species that has come into the United States and we're trying to reduce its natural advancement," Adkins said. "At this point, 70 percent of our hardwood forests are not affected by the gypsy moth, and the U.S. Forest Service is wanting to keep it that way."

The hope is that the flakes prevent the moths from mating and creating more caterpillars, which are destructive to hardwood trees.

Adkins said the gypsy moth caterpillars feed on more than 300 types of trees and shrubs, with oak trees being their meal of choice. The caterpillars consume as much leafy material as they can as quickly as possible, often leading to the destruction of the tree.

High levels of gypsy moth caterpillar excrement, known as frass, also have the potential to contaminate water supplies.

Steve Burke, environmental health director for the Delaware General Health District, said his agency supports the use of the pheromone to combat the moth. Burke, who lives in the designated treatment area, said he knew of no adverse reactions caused by Disrupt II.

"I'm not concerned at all about the health effects," he said. "It's been used for a long time in the United States with no negative effects."

Doug Richmond, the city of Delaware's arborist, said he was relieved the state planned to useDisrupt II and not harsher pesticides.

"From the research that I've done on it, it is a very safe practice to keep the gypsy moth at bay," he said.

Richmond said the city could lose almost all its oak trees in as little as three years due to a gypsy moth infestation. He said the city still is dealing with the destruction caused by the emerald ash borer, an invasive beetle that feeds on and eventually kills ash trees.

The state has other pesticides in its arsenal to fight the gypsy moth. In isolated areas with active gypsy moth infestations in Franklin County, the state will use Gypchek, a virus that affects only gypsy moth caterpillars.

The state previously had planned to use a pesticide known as BTK to target areas with gypsy moth infestations, but switched toGypchek after residents and public officials raised concerns that BTK could also kill butterflies and other insects.

Keller was not swayed by arguments in favor of Disrupt II.

"Until you're able to tell me what 81.2 percent of it is ... I can't give consent for it to be spread on our citizens," she said.

Fourth Ward Councilman Andrew Brush said he supported the treatment because his ward has a large number of old-growth oak trees that he and its residents value highly. He added that the department of agriculture had the legal authority to go ahead with the treatment without the city's consent, meaning returning the letter was more of a courtesy than a stamp of approval of the project.

Mayor Carolyn Riggle said she approved of the treatment because she trusted the opinions of the experts who told the councilDisrupt II is safe.

Adkins said this isn't the first time the department had treated the city for the pest. In 2009, the city paid for treatments near Central Avenue after a gypsy moth infestation occurred.

Since then, Adkins said treatments have largely knocked gypsy moths out of the county.

The department of agriculture also will useDisrupt II in Powell, Orange and Liberty townships and multiple communities in northern Franklin County.