Another discovery of a tiny insect that often carries an incurable tree-killing disease demonstrates how California’s citrus industry is fighting a war on several fronts -- in the orange groves, at airports and at the borders.
The California Department of Food and Agriculture said Friday that a detection dog working with inspectors on Wednesday found a package at a FedEx depot in Sacramento that contained at least 100 live Asian citrus psyllids.
Inspectors trapped the insects, sent them off to a lab, and were relieved to find that the group of psyllids were not carriers of a deadly citrus greening disease called Huanglongbing, or HLB.
This was the second discovery of the bug at a shipping depot in the last two months.
Experts said it demonstrated that the insect was making its way into the state as a passenger in packages from other states and abroad at the same time psyllids were hopping over the border from Mexico and establishing colonies in Southern California.
Psyllids often carry citrus greening disease, which is ravaging Florida’s orange groves. It has destroyed citrus farming in much of Asia and parts of Brazil and threatens California’s $1.6-billion citrus industry.
The latest discovery is similar to an incident at a FedEx depot in Fresno last month. A detection dog found curry leaves shipped from India that contained juvenile psyllids that were carriers of the disease. The insects were destroyed.
In Sacramento, the dog detected a parcel of psyllid-infested curry leaves and guavas shipped from Texas, which also has a psyllid population but so far has not detected any evidence of citrus greening. So far, the nearest outbreaks of citrus greening have been in Louisiana and Mexico’s Yucatan Peninsula.
“We know that this has been going on, but it is just now that we are getting a feeling for how bad it is as we get more federally funded dog teams out there,” said Beth Grafton-Cardwell, a UC Riverside entomologist based in the San Joaquin Valley. She said the latest find demonstrates how many ways the disease can get into the state.
What officials fear is that a diseased bug will get loose from a shipping depot and infect a nearby citrus tree.
Over the last year California has developed its own population of psyllids -- migrants from Mexico -- but none so far has proved to carry citrus greening. However, if the bugs feed on an infected tree, they probably would spread the disease around the state.
So far, officials have trapped uninfected psyllids in Los Angeles, Orange, Imperial and San Diego counties. The most recent find was earlier this week, when inspectors caught an adult psyllid insect on a calamondin, a type of miniature orange tree, in the Echo Park neighborhood of Los Angeles. State agriculture officials have set hundreds of traps in Echo Park and the other neighborhoods where the bug has been found in an attempt to both track and contain the insect’s migration.
Entomologists expect the bug to make its way up to the prime citrus growing regions of Ventura, Kern, Tulare and Fresno counties over the next year or two.
“It’s only a matter of time before the Huanglongbing disease finds its way to California from Mexico or elsewhere,” Grafton-Cardwell said this week.
A psyllid infected with citrus greening 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. There is no known cure.