By PAT MAIO pmaio@nctimes.com
An insect once thought to be in decline in
San Diego and Riverside counties has begun an alarming comeback and threatens
the area's $219 million citrus industry.
The head of a state research board says the
pest has multiplied extensively in Riverside County ---- particularly in Hemet
and Perris ---- with growers in the Temecula area now placed on "high
alert" for the Asian citrus psyllid, which typically carries a disease
that is deadly to citrus trees. Migration of the bug is headed south into North
County.
While the bug has appeared throughout
Southern California since 2009, the disease has been found in only one place in
California. In March, a lemon tree was found to be infected in a Hacienda
Heights neighborhood in Los Angeles County.
The Asian citrus psyllid is a tiny, aphidlike
insect that can carry a devastating plant disease called huanglongbing, also
known as citrus greening disease. The disease destroys the taste of citrus
fruit and juice, along with the production, appearance and value of citrus
trees.
While the bug was first detected back in 2009
in cities along the Mexican border in San Diego County ---- as well as Valley
Center ---- the psyllid was detected for the first time ever in Fallbrook on
June 11. The bug hadn't been spotted in Valley Center since 2009, but was
detected again July 16 in a trap there, state officials said.
A meeting with state agricultural officials
and growers and the public has been scheduled for Aug. 7 at the Valley Center
Public Library to discuss treatment of infected trees and outline the extent of
the bug's migratory movement.
"There has been a considerable increase
in psyllids. We are starting to see the population of (Asian) citrus psyllids
move south out of Riverside County. They are hitchhiking," said Ted
Batkin, president of the Visalia-based California Citrus Research Board.
"The threat to North County is the movement from Riverside and not from
the border. We are tracking up to hundreds of psyllids, so statistically this
means the population is into the thousands."
Batkin noted that the bug had been on the
decline since first spotted along the Mexican border a few years ago, but that
hundreds of traps in groves have caught enough of the bugs during the spring
and summer breeding season to begin sounding alarm bells.
"There has been a considerable
increase," said Batkin in an interview Tuesday before meeting with
Riverside citrus growers at the board's research laboratory in Riverside.
"Ultimately, the psyllids bring the bacterium with them. The growers in
Fallbrook and Pauma Valley area have their eyebrows raised. They are on high
alert."
Once a citrus tree becomes infected with the
disease, there is no cure and the tree will eventually die ---- in three or
four years for a 30-year-old tree or six months for a young one.
Growers are jittery over this discovery
because the disease carried by the psyllid wreaked havoc in Florida and Brazil,
and could do the same in California's $2 billion citrus industry.
"I think if you look at the science of
the creature, and the infection that it's carrying, it's a reasonable
conclusion that it could wipe out the industry," said Charley Wolk, a
Fallbrook-based manager of avocados and citrus groves in the region. "When
you find multiple findings of psyllids, that's not crying wolf. Yeah, I'm
concerned, but what can you do? I can't go out with a fly swatter and kill
psyllids."
Lisa Leondis, head of San Diego County's
department of Agriculture, Weights & Measures, said the mere discovery of
the psyllids locally means that quarantines for the areas where the bugs were
found ---- including Fallbrook and Valley Center ---- will be extended for
another two years. Quarantines already cover most of Riverside and San Diego
counties, she said.
A quarantine means that citrus fruit can't be
moved out of the county, unless it is clipped of stems, leaves and twigs,
according to Leondis. Citrus trees grown by a certified nursery, though, can be
shipped out, she said.
"It's not a pretty picture," said
Leondis, who is cautiously optimistic that the region will avoid the fate of
Florida and Brazil. "We are in this for the long haul. We have to treat
the trees."
The citrus psyllid bores into new leaves
sprouting on the tips of branches and lays eggs. The pest generates a white,
gooey substance in the area where the psyllids have infected the tree. The
psyllid looks like a tiny thorn protruding from the underside of a leaf at
about a 45-degree angle.
An Asian citrus psyllid was last found in
North San Diego County in a tangelo tree in Valley Center in late 2009. San
Diego's citrus industry, including fresh fruit and trees, was valued at $78
million in 2011 in San Diego County, and $140.5 million in Riverside County,
according to the latest figures provided by the counties.
"The citrus industry is part of
California's heritage," said Steve Lyle, a spokesman with the state's
Department of Food and Agriculture in Sacramento.
At the Valley Center meeting on Aug. 7, Lyle
said state agricultural officials will explain treatment programs to help kill
the psyllids, including spraying the trees with pesticides, and treating the
soil so that tree roots absorb the pesticide and attack the bugs as they bore
into the leaves.
"We won't eradicate the psyllid, but we
are looking to contain it so that when the disease arrives, we will be able to
minimize the damage," Lyle said.
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