A tiny disease-carrying insect that could bring down California’s $1.6-billion citrus industry continues an inexorable march north into one of the nation’s premier orange- and lemon-growing regions. State officials said Wednesday that they had found the bug in Echo Park, the northernmost spotting yet.
Routine traps captured a single Asian citrus psyllid on a citrus tree at a home in the Los Angeles neighborhood Monday. The California Department of Food and Agriculture is now setting up hundreds of traps in an 8-square-mile area around the home where the insect was discovered.
The detection of the bug in Echo Park also triggers a quarantine in which the agency will restrict the movement of citrus plants within five miles of the find. State officials are also considering a ground-based pesticide spraying program.
The insect was found on a calamondin, a type of miniature orange tree. Inspectors sent it to a lab to determine if it is a carrier of citrus greening disease, also called huanglongbing, or HLB. So far, the nearest outbreaks of citrus greening have been in Louisiana and Mexico’s Yucatan Peninsula.
When carrying the disease, the psyllid spreads it when it feeds and then skips from tree to tree. The disease ruins the taste of fruit and juice before killing the plants. Citrus greening has ravaged many tens of thousands of acres of Florida orange groves and is starting to show up in the Yucatan Peninsula and Louisiana. There is no known cure or prevention.
“It’s only a matter of time before the huanglongbing disease finds its way to California from Mexico or elsewhere,” said Beth Grafton-Cardwell, a UC Riverside entomologist based in the San Joaquin Valley.
The Echo Park discovery, which comes on the heels of a similar find in Santa Ana this month, is “telling us the pest is rapidly moving through the state, and we have to work even harder in tracking the pest to prevent a death sentence to California citrus,” she said.
California’s best hope is to keep the psyllid population low through trapping and pesticide treatments, and to slow the geographic spread of the bug. The state also must be able to detect and eradicate any trees with the disease early in its arrival, before it has time to reach commercial groves, she said.
Grafton-Cardwell said the good news so far is that homeowners are starting to help in the efforts to find the insect, and that none of the bugs trapped in San Diego, Imperial and Orange counties over the past year was a carrier of the disease.
She said that homeowners should examine the new, small leaves of their citrus trees for signs of brownish, aphid-sized adults or nymphs -- flat, yellow-orange disk-shaped bugs with red eyes -- to see if psyllids have landed in their yard.
Additionally, if homeowners see uneven, yellow mottling of the leaves, they should call the agriculture department hotline at (800) 491-1899 to have an inspector determine whether their plant has the disease, she said.
More information is available at www.californiacitrusthreat.org.
The rapid discovery of new psyllid colonies is not unexpected. Just a year ago, the first colonies jumped the border from Mexico and settled in San Diego and Imperial counties. Entomologists believe they will move north into the state’s prime citrus-growing regions, including Ventura, Kern, Tulare and Fresno counties.
Agriculture officials should not take solace from the fact that none of the psyllids caught and tested so far has carried the disease.
“It tells us that we still have not found a hot spot for the disease. It doesn’t mean it’s not out there; it’s just that we have not found it,” said Ted Batkin, president of the Citrus Research Board in Visalia, an industry group that is working with state and federal officials to contain the insect and the disease it typically carries.
He believes inspectors will uncover more psyllid populations, probably elsewhere in Orange and Los Angeles counties as well as San Bernardino and Riverside counties in the coming months. The insect remains dormant for much of the year but tends to move around in the fall because it likes to lay eggs on the new growth of citrus trees, Batkin said.
Grafton-Cardwell said the bugs often establish colonies near major roads and freeways. People move plant material around, and the psyllid hitches along, she said.
California had a close call last month when an inspection dog found a plastic bag of curry leaves that contained one dead adult psyllid and nine live juvenile insects, or nymphs, in a duffel bag from India at the FedEx depot in Fresno.
Tests subsequently found that the nymphs were infected with the disease. Inspectors believe they destroyed all of the insects but noted that if the psyllids had not been detected, they could have launched the infection in California.
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Homeowners, check your trees
For homeowners concerned about Asian citrus psyllids on their citrus trees, the state recommends careful inspection. It can take years for symptoms of the disease to appear, which means inspection for the psyllid is the best line of defense, state officials say. They recommend:
* Using a magnifying glass or hand lens.
* Inspecting when watering, pruning or tending trees.
* Paying close attention during times of leaf growth or “flushing.”
* Acting quickly if something suspicious is found. Secure the psyllids in a clear sandwich bag, jar or plastic container, and contact your local agricultural commissioner’s office or call the California Department of Food and Agriculture’s hotline, (800) 491-1899.
Source: California Department of Food and Agriculture