'Tree killer' disease that targets citrus found in Santa Paula; state orders quarantine

The state declared a citrus quarantine across roughly 101 square miles of Ventura County Tuesday, two weeks after the agency discovered an incurable, citrus-killing bacteria infecting two trees at a Santa Paula home.

Local growers have long harbored concerns about huanglongbing, the deadly bacterial disease referred to as HLB or citrus greening. Much is at stake. Lemons were the county's third-most valuable crop in 2022, according to the Ventura County Agricultural Commissioner's Office, and citrus altogether was worth more than $250 million.

The disease, spread by a tiny, mottled brown insect called an Asian citrus psyllid, has caused a 70% reduction in Florida's orange crops since 2005, researchers say, and officials have already found it and imposed quarantines in Los Angeles, Orange, Riverside, San Bernardino and San Diego counties.

Citrus psyllids first were spotted in Ventura County in 2010, but officials found no trace of the long-feared disease in the county until late last month, when staff from the California Department of Food and Agriculture, or CDFA, captured a psyllid carrying the disease in Santa Paula.

"This really is a devastating find,” Ben Faber, a farm adviser from the UC Cooperative Extension, said in a Sept. 22 statement announcing that discovery. "The disease is a tree killer."

Tuesday's quarantine came after CDFA staff delved further and found that the disease had already infected a lime tree and orange tree on the property, according to the CDFA's Citrus Pest and Disease Prevention Program.

The quarantine order — covering a rough 5-mile radius circle drawn around the site of the infection — bars the transport of any citrus tree or material outside the area. Fruit can still be transported across the boundary, but only after growers have taken steps to spray or clean it to ensure it doesn't carry any psyllids.

Everyone from homeowners with backyard orange trees to large-scale lemon growers are included in the order, which covers an area bordered on the north by Ojai Road, on the south by East Los Angeles Avenue, on the west by Wells Road and on the east by Balcom Canyon Road.

In a statement, the CDFA asked residents within the quarantine zone to follow three steps to protect citrus trees:

• Do not move citrus plants, leaves or foliage into or out of the quarantine area or across state or international borders. Keep it local.

• Cooperate with agricultural officials placing traps, inspecting trees and treating for the pest.

• If you no longer wish to care for your citrus tree, consider removing it so it does not become a host to the pest and disease.

Up-to-date information and a map of quarantine zones across the state can be found at www.cdfa.ca.gov/citrus/pests_diseases/hlb/regulation.html.

Quarantined 'for the rest of our existence'

Ventura County Agricultural Commissioner Korinne Bell said the quarantine "chews up" much of the county's citrus growing area: over 8,600 acres.

The quarantine hasn't affected any large plant nurseries so far, Bell said, but there's a risk the zone could expand to cover a few production nurseries located along Highway 126. That would mean they wouldn't be able to sell citrus plants at all outside of the quarantine boundaries.

CDFA staff have also carved out a 250-meter-radius zone in the residential area around the first pair of infected trees where they are testing for further infections, destroying infected trees and treating trees to kill psyllids.

If officials do find more infected trees, they will expand the quarantine zone in a 5-mile radius around the new site, Bell said.

Faber said in an interview Thursday that the quarantine will probably be in place "for the rest of our existence," and that it's likely that more infected trees will be found and the quarantine will expand.

The state has never lifted an HLB quarantine to date, Bell said.

HLB can infect a tree for three to five years before it's detected, Faber said. That means the two infected trees in Santa Paula have likely been carrying the disease — and providing a launchpad for more disease-carrying psyllids — for at least three years.

Even if no other infected trees are found, both Faber and Bell said the quarantine puts the future of the county's citrus industry in question, especially with the value of lemons at a low point in the last few years.

"In the context of a grower's world right now, there's water, there's labor. The market is terrible. They don't make any money," Faber said. "Now, you add this other straw to this lemon camel's back?"

The treatments required to make quarantined fruit safe to send to market — measures like pesticide sprays and post-pick cleaning — cost money, enough in some cases to make lemons no longer worth it.

Faber said the disease, combined with rough market headwinds, could spell the long-term death of the county's lemon industry and require farmers to find new crops to replace them.

Bell said there is still a little hope. The county's climate is different from Florida's, which Bell said might cause the disease to behave differently. Lemons, she said, are slightly less susceptible to HLB than the oranges and mandarins that dominate Florida's citrus industry.

County growers have also taken lessons from Florida's experience, pushing hard to curb psyllid spread and managing to keep the disease at bay while it spread throughout much of the rest of Southern California. Bell said she hopes similar efforts will help to slow the spread in coming years.

But the immediate consequences of HLB's discovery, she said, are still unfolding.

"You might see lemons pulled out, leasing the land for row crops," Bell said. "We have to wait and see how many more (infected trees) we have."

Faber said county residents should keep a sharp eye on their backyard trees and carefully follow the state quarantine order. Citrus psyllids can't fly very far, he said, and humans transporting citrus trees and fruit are largely responsible for their spread around the globe.

"We're our own worst enemies," he said.

Isaiah Murtaugh covers education for the Ventura County Star in partnership with Report for America. Reach him at isaiah.murtaugh@vcstar.com or 805-437-0236 and follow him on Twitter @isaiahmurtaugh and @vcsschools. You can support this work with a tax-deductible donation to Report for America.

This article originally appeared on Ventura County Star: Citrus-killing disease triggers quarantine around Santa Paula