Pesticide use down on farms in state

California farmers used 10 million fewer pounds of pesticides on crops last year, but strawberry growers increased their reliance on fumigants, which are considered among the most dangerous pest-killing chemicals, according to a state report released Thursday.

Mirroring a three-year trend, the state’s farmers used smaller volumes of some of the most hazardous pesticides. Compounds linked to cancer or affecting reproductive and neurological functions declined by 2.5% to 9.3% in 2006, according to the California Department of Pesticide Regulation report.

But the state’s strawberry growers, primarily around Oxnard and in the Salinas and Watsonville areas, applied fumigants to 5,000 more acres, using 132 more tons of the chemicals than in the previous year, according to the state’s data. That is a 9% increase in acreage treated and a 3% increase in tonnage.

Fumigants are toxic gases that are injected into soil to kill a broad spectrum of weeds, insects and other pests. Traces evaporate from the soil, raising the risk that farm workers and nearby residents will inhale them.

Statewide, 190 million pounds of commercial pesticides were used in 2006, a 3% decline from 2005, the state report says. The tonnage used on farms dropped nearly 6%, while the amount used for other purposes, such as landscaping and mosquito control, increased.

Most agricultural pesticides are applied in the San Joaquin Valley, led by Fresno and Kern counties.

Ventura County, which grows much of the nation’s strawberry crop, ranks eighth.

Mary-Ann Warmerdam, director of the pesticide agency, said that the state “works hard to promote least-toxic pest management” and that the new data show “our efforts are paying off.” But she acknowledged that “we have more work to do.”

A major fumigant, methyl bromide, has been banned under a United Nations treaty that protects the ozone layer, although special exemptions allow it to be applied in some places, particularly in California and Florida.

California’s strawberry growers used more methyl bromide last year than the previous year: The tonnage increased by 5% and it was applied to an additional 2,200 acres of strawberries, or 13% more, according to the state data. The volumes were slightly less than 2004’s 3.2 million pounds.

Carolyn O’Donnell, a manager of the California Strawberry Commission, said Thursday that she suspects that the industry’s fumigant use increased because more acres were planted.

“I think over the long haul, you will see a decrease in use,” she said. “We’re looking at all the ways we can phase out methyl bromide as fast as we can.”

marla.cone@latimes.com