New U.S. Rules Extend Medfly Spraying Period : Farming: Officials say the change for growers is tied to the fly’s longer life cycle during cooler winter months.

Under new rules to be announced today, growers in Ventura County’s Medfly quarantine area must spray their crops with pesticide for at least five weeks--and as long as 11 1/2 weeks in cooler weather--before harvesting.

The regulations call for some spraying periods that are nearly three times as long as had previously been outlined, a change officials tied to the fly’s longer life cycle during the winter. Under the new schedule, crops must still be sprayed every six to 10 days, but the length of the entire treatment will vary, depending on the time of year.

Officials with the federal Department of Food and Agriculture will explain the spraying guidelines to growers of avocados--the largest crop to be affected by the Mediterranean fruit fly infestation--during a meeting this morning in Santa Paula.

While the treatment schedule will not prevent growers from picking in time for the January and February markets, the requirements could make it more difficult to capture premium prices.

“It’s bad enough trying to do things on a one-month time frame,” said rancher Bill Butchko, who cultivates about 25 acres of avocados near Somis. “If it’s going to be in effect for almost two months, certainly that’s all the more harder to try and plan.”

Under normal circumstances, Butchko said he would gauge market prices, coordinate with a packinghouse and schedule a harvest about two weeks in advance.

“If conditions change for the better or against you, you can speed up your harvest . . . or curtail it or chop it off entirely,” he said.

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With the restrictions on harvesting, growers also will have less flexibility to pick avocados quickly if forecasters call for a crop-damaging freeze.

Steve Peirce, a consultant with Calavo Growers of California, an avocado cooperative that represents 204 grove owners in the quarantine area, said it is difficult to predict how many farmers will elect to begin spraying. Some, he said, may try to wait, hoping the quarantine will be lifted while the fruit is still usable.

In past years, Calavo handled 15% of its Ventura County crop during December, January and February. Last year, when the crop was unusually large, that amounted to about 12 million pounds, said Carlos Vasquez, a regional manager with the cooperative.

The most popular wintertime varieties in Ventura County are Bacons and Pinkertons, officials said, while the largest crop, Hass avocados, are usually harvested later.

To recover the cost of the pesticide spraying, Butchko said some growers may elect to pick part of their Hass crop early along with the other varieties.

After the first two Medflies were discovered in Ventura County on Sept. 29, growers within the 86-square-mile quarantine were told they had to fumigate, put their crops in cold storage or spray them with a mixture of malathion and corn syrup bait before they could sell them.

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Previously, state and federal officials had described the spraying treatment--which is expected to be the most popular option--as a monthlong process with weekly sprayings.

Treatment lengths will now vary, growing longer through January and February, then shortening as temperatures warm. For instance, if a grower began spraying Monday, he or she could harvest Dec. 25.

If the quarantine is still in effect June 1, treatment lengths will return to one month. So far, seven growers have begun spraying, hiring either ground crews or helicopter companies to blanket the crops.

Doug Hendrix, spokesman for the Cooperative Medfly Project, said the longer lengths should not come as a surprise. He said growers were cautioned that the four-week model was based on warmer temperatures in Corona and during the summer in Ventura County.

“We told them this could possibly change to follow the biology of the fly, so this isn’t going to catch them by surprise,” he said.

But Rex Laird, executive director of the Ventura County Farm Bureau, said he had expected the treatment length to remain at one month.

“If they were talking about 30 days before and now it’s more like 45, that may surprise some folks. It does me. I didn’t realize there was going to be a climatic adjustment,” he said.

John Grether, who owns about 150 acres of avocados inside the quarantine zone, said the inconvenience of the longer treatment schedule is outweighed by the need to wipe out the fly and bring an end to the quarantine.

“What we want to achieve foremost is to eradicate the fly,” he said. “We’re willing to cooperate with any program that has good science and good reasoning behind it.”