Winged invaders

The small town of Dixon has become ground zero in the fight to stop the Mediterranean fruit fly after the dreaded agricultural pest was discovered there last week in its first appearance in the Central Valley since the early 1980s.

Government officials have embarked on an urgent campaign to stop the invader, including a quarantine of area produce, before the Medfly can spread through one of the world's most productive farming regions.

"It's what we classify as a biological emergency," said Steve Lyle, spokesman for the California Department of Food and Agriculture. "We're moving as fast we can to eradicate the pest."

Since a small number of larvae were found last week in a backyard peach tree, dozens of government workers have descended on Dixon's residential neighborhoods.

Going door to door, they have stripped fruit from trees at homes within 100 meters of the discovery site. They also conducted a ground-spraying campaign in a 200-meter radius using organic compounds -- not Malathion, the pesticide used to kill Medflies in a controversial aerial spraying campaign in the 1980s.

Fruit trees in Dixon are being inspected for larvae, and traps set throughout the region are regularly monitored for adult flies.

State entomologist Mark Lubinski said the teams have so far found a total of 12 or 13 flies and 33 larvae in several locations in central and east Dixon.

Most likely the Medflies came from Hawaii, brought home in the bags of vacationers, he said.

To prevent the insect's reproduction, millions of irradiated, sterilized male Medflies -- dyed pink to distinguish them from the wild flies -- are being dumped from airplanes. Females can breed only once in their short lifetime, and mating with one of the sterile males produces no offspring.

Agriculture officials on Tuesday quarantined a 114-square-mile area around Dixon, preventing many kinds of produce from leaving the area except under strict conditions.

The move left farmers struggling to cope during their peak harvest season.

On Wednesday, under a blustery sky quickly filling with clouds, Nigel Walker stood amid his rows of ripening heirloom cherry tomatoes.

Walker, owner of the organic Eatwell Farm northwest of Dixon, had resigned himself to the idea that the tomatoes he had tended all summer might never reach the hundreds of Bay Area customers for whom he'd grown them.

Because of government regulations, Walker is unable to ship his tomatoes, eggplants, plums and other summer produce in which Medflies prefer to lay their eggs.

"I can't move any of it off the farm," he said.

Walker also feared that rain predicted for the Sacramento area could ruin much of his crop, causing the tomatoes to split, he said.

As a small farmer who grows about 50 crops on 65 acres, Walker said he does not have the crop insurance available to those who plant hundreds of acres in a single crop.

He estimates the potential cost to his farm at $8,000 to $10,000 a week for the next six weeks, until the summer produce runs out.

Yet Walker says he agrees with the quarantine because he doesn't want other farmers to be ruined.

"I fully support what they are doing," he said. "You've got to hit the Medfly hard, right here in Dixon. We'll lose our livelihoods if this spreads."

To the east of Dixon, Gene Robben and his sons are among the area's largest growers.

They are able to ship tomatoes to processing plants but only by complying with regulations that they deem overly restrictive.

All the flies and larvae found so far have been in residential areas of Dixon, not the surrounding farmland, said Spencer Bei, one of the farm's owners.

"They're taking tomatoes and other crops where no Medflies have been found and making out flies to be a problem," he said.

To prevent spillage, tomato trucks have to be covered with tarps or shipped less than full, increasing freight costs.

Tomato waste then has to be trucked back from the canning facility to the farms and plowed under.

"We have no choice," Bei said. "If we want to harvest our crop, we've got to play by the rules."

The rain threatening the tomatoes could make the whole situation moot and lead to farmers filing insurance claims instead, said Gene Robben.

The quarantine is expected to last well into next year and perhaps longer if more flies are found, farmers and officials said.

The source of so much angst and frustration is the fly's larvae -- tiny wormlike creatures that look like grains of rice and feed on fruits and vegetables.

Alicia Ruiz, a state pest control specialist, found four or five Medfly larvae last week in peaches in a neat backyard garden on a cul-de-sac in central Dixon.

Peaches with their soft, sweet flesh are the Medflies' favorite breeding spots, she said. But the larvae also take to kumquats, persimmons and citrus.

"After the infestation is big, they attack everything," she said. "Every fruit is wormy."

Mediterranean fruit flies -- introduced to the state in the 1960s -- can consume and destroy an estimated 260 crops grown in California, Lyle said.

"If you're eating fruits and vegetables for a meal, the fruit fly is probably interested in them," he said.

The fruit flies have wreaked havoc in Hawaii, Central and South America, Africa and the Mediterranean.

An infestation can make fruit inedible and cause it to drop too early from the tree. If not stopped quickly enough, a full-blown fruit fly infestation can devastate entire crops and the agricultural economy.

"Our goal in California is never to let it get to that stage, and we never have," Lyle said.

About the writer:

• The Bee's Hudson Sangree can be reached at (916) 321-1191 or hsangree@sacbee.com.