FRESNO -- A California judge dealt a major setback to the state's campaign against an invasive moth on Thursday, ruling that aerial sprays must halt over Santa Cruz County until agricultural officials do a full environmental review of their anti-pest program.

The ruling could keep planes from spraying a pesticide targeting the light brown apple moth for up to a year, while the state studies the spray's effect on people and the environment, said county spokeswoman Dinah Phillips.

Secretary of Food and Agriculture A.G. Kawamura vowed the state would appeal the ruling immediately. In a statement, he said the decision was delaying "the safest, most progressive eradication program available."

After meeting with lawmakers and environmentalists, Gov. Arnold Schwarzenegger said Thursday the state would postpone aerial sprays over the county until Aug. 17, when further "acute testing" of the human health effects of a chemical sprayed over the central coast last year would be complete. The original date had been June.

"The light brown apple moth is a serious threat to California's forests and agriculture. If left uncontrolled, the moth would have a devastating impact on our state's environment and economy," Schwarzenegger said in a statement.

Hundreds of people complained of feeling sick when planes applied the first round of spray in the area surrounding Monterey and Santa Cruz last fall. State environmental health experts recently said those reported illnesses can't conclusively be tied to the pest eradication efforts.

Soon after the sprays, the county and city of Santa Cruz sued the state, saying Kawamura broke state law by authorizing the aerial campaign without the benefit of environmental review. Environmentalists filed a similar suit in Monterey County Superior Court, which is scheduled to be heard May 8.

Judge Paul Burdick ruled Thursday morning that the state had not proved the moth infestation constituted an emergency, a category that would have allowed authorities to avoid the lengthy state review process.

Steve Lyle, a spokesman for the California Department of Food and Agriculture, did not say how Burdick's decision would impact the state's plans to spray in other counties, but he said his department was focused on the appeal.

Assemblyman John Laird, D-Santa Cruz, who has written two bills critical of the program, said he hoped the ruling would "make way for additional science-based, independent third-party review" of the state's plans.

Dozens of Santa Cruz residents rejoiced on the courthouse steps Thursday, Phillips said.

"When the judge announced his decision, a tremendous cheer was raised," she said. "I can still see dozens of people outside my window giving each other high fives."

Some residents say they believe the state should complete an environmental review.

"I think they need to investigate more, i think because there's a lot of controversy about it," says Rachel Malsbury who lives in Santa Cruz.

Many local farmers say they are disappointed by the ruling.

Steve Bontadelli is a farmer near Watsonville and president of the Santa Cruz Farm Bureau, which has more than 1,400 members.

Bontadelli says the apple moth poses a real threat to farmers.

He fears that any delay could be costly to farmers and the region's economy if the apple moth population grows out of control.

"The problem is if this moth is allowed to establish itself in the only place in North America right here, we could end up being quarantined from the rest of the country and other countries and cause ourselves some severe economic impact," Bontadelli says.

Agriculture officials did not immediately respond to calls seeking further information about the ruling's impact in the San Francisco Bay area, where authorities also plan to send up planes to drop a fine chemical mist to combat the moth.

Officials with the U.S. Department of Food and Agriculture have said the agency may go ahead with the spray campaign regardless of the ruling because the moth threatens to destroy millions of dollars' worth of valuable crops.

Meanwhile, Sonoma County officials said they've recorded a second light brown apple moth finding since the invasive pest was first detected in the heavily agricultural county in February.

Officials there said they don't have any immediate plans for aerial spraying, and instead would continue their ground-based campaign.