SAN DIEGO - The San Diego County Board of Supervisors on Wednesday gave tentative approval to a program to reduce the number of eye gnats around organic farms -- without the use of pesticides.

The tiny insects live and breed in warmer climates and are a nuisance to humans and animals, buzzing around the eyes, nose and mouth, according to Jack Miller, director of the county's Department of Environmental Health.

Certain farming operations, particularly organic, can increase breeding and create a public nuisance for neighboring residents, he said.

"Organic farms have the greatest potential to create eye gnats because they cannot use the traditional pesticides and they turn vegetation back into the soil, providing food for the eye gnats," Miller said.

The insects that originated on two large organic farms in south Escondido and the East County community of Jacumba had a considerable negative impact on residents and visitors, according to county documents. In November, staffers were directed to work with the Farm Bureau and come back with options to address the problem.

Of the 344 organic farms in the county, only those two caused significant eye gnat problems in neighboring communities. One closed and the other was voluntarily taking control measures, Miller said.

The initial plan presented in March would have allowed the spraying of pesticides, if lesser measures failed, but was done away with largely because of opposition, Miller said.

"We have a viable and strong program without the use of pesticides," Miller said.

County staff would investigate complaints regarding commercial farms. Those identified as nuisance sources would be required to implement abatement procedures if voluntary measures -- including traps, barriers around the farms and a ban on turning fresh produce into the soil -- did not work, Miller said.

The program also includes last-resort provisions if voluntary and mandatory efforts fail -- restricting the types of crops grown or ordering a farmer to use effective control measures, regardless of cost. Farms would not be ordered to close.

The proposed program adds eye gnats to the definition of "vector" in the county code and applies to all nuisance sources of eye gnats, which would allow the county access to funding sources that would help support research for solutions to eye gnat breeding, Miller said.

It would also establish an eye gnat abatement appeals board.

"The approach in this ordinance is very measured, it's very reasonable and certainly provides plenty of opportunity for organic farmers who find themselves in the situation where they have an eye gnat problem to address and correct ...," Supervisor Greg Cox said.

County officials found no substantial evidence that the project would have a significant effect on the environment.

The vote was 4-0. Supervisor Bill Horn recused himself because he is a registered organic grower.

An adoption vote was scheduled for Dec. 5.