Inland growers moving quickly to prepare for Asian citrus psyllid

A tiny pest just south of the U.S. border with a taste for budding citrus trees has state agriculture officials and growers on high alert. Its arrival could mean doomsday for an industry that was worth $1.8 billion in California last year, they say. In recent weeks, the Asian citrus psyllid, an insect the size of a pea that can carry a rapidly spreading disease dubbed "greening," inched closer to California's southern border.

All it takes is one bite, said Chris Boisseranc, a pest control adviser for Corona-based Entomological Services Inc. who works with growers from Blythe to Irvine. "If it did come into the state, it could be one of the most devastating pests to hit the industry ever," he said. When a psyllid infected with the "greening" disease bites into a tree, the tree doesn't stand a chance.

"It kills the trees, but before it kills the tree, it ruins the fruit so that it is not edible. It is bitter, sour and misshapen," said Tom Shea, a Riverside County master gardener who specializes in citrus. Florida, a state where citrus, largely for juice, is worth more than $9 billion annually, has had "greening" spread to 31 of its 67 counties since 2005, the year the disease was first discovered.

Florida spotted its first Asian citrus psyllid in 1998. "We tried to control it, tried to eradicate it when it came, but it just spread so rapidly," said Denise Feiber, a spokeswoman for the Florida Department of Agriculture. Feiber said the state doesn't expect ever to eradicate the pest completely.

Florida officials have been recommending that backyard gardeners avoid planting citrus trees. For nurseries, the state requires new trees to be grown indoors, where they can't be reachable by pests. For growers, the state has worked with universities to develop more disease-resistant trees and required citrus producers, packers, harvesters and nurseries to register with a database.

Close scrutiny has been essential in keeping a watch on where the disease spreads.
"It used to be a casual glance out the truck on your way to breakfast," Feiber said, of growers checking their groves. "Now, you've got to get out of the truck and look at every tree."

The 21,447 acres of oranges, grapefruits and lemons harvested in Riverside and San Bernardino counties last year were worth $127.9 million. So far, state agriculture officials have not detected the pest in California, said Steve Lyle, spokesman for the California Department of Food and Agriculture. But it has been detected in Tijuana, Mexico, not far from San Diego County's stretch of the border

Traps in Beaumont

Tom Carmody, chief executive officer of Perricone Juices, which bottles fresh fruit using California-grown citrus, has allowed the U.S. Department of Agriculture to set up traps for the psyllid on his property in Beaumont in case it does cross the border and travel north into Riverside County. So far, there's no sign of the pest, he said.

"It would be devastating to California," he said. "My business would be down the chain because the groves would be affected first." The citrus industry was recently hit by an unusually brutal freeze that enveloped Southern California early last year.
"We're back from the freeze. We will not come back from this disease," Carmody said.

For a production grove, the losses can amount to $1,000 to $5,000 per acre each year, for three years, the amount of time it takes a new tree to grow and bear fruit, Boisseranc said. That is if the new trees don't become infected. Growers run the risk of nearby infected pests returning to feast.

Intense Inspection

Boisseranc warned that homeowners with citrus trees in their backyards shouldn't think of spraying pesticides on their trees until an agriculture official has confirmed they might have an Asian citrus psyllid in their midst.

It's the same advice he's giving grove owners. The best prevention is intense inspection of the leaves and budding growth on the trees, he said. Preventative pesticides could upset efforts to drive away other pests, and it shouldn't be done in haste, he said.

Boisseranc said the infection's difficult detection is similar to that for Pierce's disease, carried by glassy-winged sharpshooters, which wreaked havoc on Temecula vineyards a decade ago and caused $20 million in damage. Pesticides and the introduction of natural predators have since kept that pest at bay.

Greater Threat

But the danger posed by the Asian citrus psyllid is much more severe, said Beth Grafton-Cardwell, an entomologist with UC Riverside. "The psyllid moves faster, farther; the disease is more aggressive and kills the plant quicker," she said.

"We could conceivably lose most of the citrus in California," said Grafton-Cardwell said. "What we're worried about is somewhere, in someone's backyard, a tree is not producing fruit, and that might be a diseased tree," she said. "In California, we have only 300,000 acres of citrus."

Riverside is home to UC Riverside's Citrus Variety Collection, where there are 1,010 different types of trees planted. The trees are already being monitored for the pest.
"We get visitors from all over the world," said Tracy Kahn, curator of the UCR Citrus Variety Collection. "Everyone's really concerned," she said.


Source: pe.com

Publication date: 8/12/2008

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