The Asian citrus psyllid and the bacterial disease Huanglongbing vectored by the pest could literally eliminate California’s $2 billion commercial citrus industry. Yet industry leader Kevin Severns of Sanger does not believe this will happen.

“I am bullish on the California citrus industry,” said Severns, a citrus producer who owns and operates Severns Citrus Farm in Sanger with his wife Cindy. “I believe the California citrus industry has a bright future ahead.”

Severns is not the only California citrus leader to assuredly speak out about the industry odds against the pest-disease threat. Severns and other believe research and other projects underway in California, the U.S., and the world will unlock a long-term solution to ACP-HLB before the threat gains a major foothold in California commercial citrus.

“I am confident that researchers will find a cultural solution for the psyllid and HLB before the California citrus industry enters a state of decline,” said Severns, a second-generation Navel orange producer.

Among the possible cultural answers include HLB-resistant citrus tree varieties and possible methods to stop the insect from spreading the disease.

Severns has confidence in the Citrus Research Board (CRB), the University of California, and other industry members working feverishly to place the threat in handcuffs. “We hope a solution is found so HLB will not be the death sentence for our citrus industry,” Severns said.

The ACP, Diaphorina citri (Kuwayama), is an aphid-like insect three-to-four millimeters long as an adult with a brown mottled body. The pest feeds on the leaves and stems of citrus trees and similar plants.

The psyllid’s actual feeding damage itself is not the major concern. The real issue is the insect-vectored disease is the world’s deadliest for citrus. Wherever the psyllid appears worldwide, HLB is on its heels.

HLB is transmitted to healthy trees by the psyllid feeding on infected-plant tissue. Every HLB-infected tree eventually dies; usually within several years of infection. An infected-tree may not show HLB symptoms — mottled, yellowed leaves — for several years. Misshapen, sour-tasting fruit from an infected tree is unmarketable.

The ACP-HLB duo has destroyed thousands of commercial citrus acres around the world. The pest was first found in the U.S. in Florida in 1998. The disease was later found in every citrus-growing county in the Sunshine State.

HLB was confirmed in Texas in January with several more positive finds found a short time later.

The Western U.S. citrus production belt — California and Arizona — is the last major citrus-growing region in the world to face HLB, Candidatus Liberibacter asiaticus. The psyllid was first found in California in 2008 in San Diego and one year later in Yuma, Ariz.

A single, positive HLB case was detected by the California Department of Food and Agriculture (CDFA) in the Los Angeles community of Hacienda Heights in a residential pummelo-lemon tree in March. The industry expected an eventual HLB find in the state since thousands of psyllids are in L.A. basin residential areas.

HLB game-changer

The HLB find rattled California’s commercial citrus industry; a $2 billion industry with about 700,000 acres of citrus statewide (2010 figure).

“The HLB find in the L.A. basin was a game changer for the commercial citrus industry,” Severns said. “We came face-to-face with the realization the disease has the potential to completely wipe out the citrus industry. HLB is a potential death sentence.”

No further cases have been found in California — residential or commercial citrus. HLB has not been detected in Arizona.

Despite the initial shock, Severns remains bullish and is backing up his optimism with his pocketbook. Instead of sitting on the fence waiting to see if HLB gains a foothold, Severns intends to plant 10 to 20 acres of Cara Cara orange nursery stock on his farm next spring.

Severns’ optimism is partially based on his knowledge of the California citrus industry. He serves as vice-chairman of California Citrus Mutual, a non-profit organization whose goal is to improve the bottom line for its 1,400 citrus-grower members.

Severns also wears the hat of secretary-treasurer of the California Citrus Pest and Disease Prevention Committee. The committee was formed last year after the California legislature passed and then-Gov. Arnold Schwarzenegger signed Assembly Bill 281 into law — legislation to add claws to the fight against ACP-HLB.

The committee has a war chest this year of about $16 million; funds collected from growers through a mandatory 7-cent-per-citrus-carton assessment.

Beyond these volunteer positions, Severns’ full-time job is general manager of the Orange Cove – Sanger Citrus Association’s packinghouse cooperative in Orange Cove. He is heavily engaged daily with citrus growers, pest control advisers, industry experts, and others.

California’s citrus industry is a large player covering 270,000 acres. It ranks second behind Florida in U.S. citrus production. California growers produce nearly one-quarter of the nation’s citrus, including 80 percent of the nation’s supply of fresh-market oranges and lemons, according to the USDA’s Economic Research Service.

Another reason for Severns’ bullish attitude is the California citrus industry has learned volumes of information from Florida’s ACP-HLB experience — its correct decisions, mistakes, and lessons learned the hard way. Severns has made several trips of Florida where leaders have willingly shared valuable information.

“Florida growers said you must control the bug to keep the disease from spreading,” Severns explained. “If we greatly limit the insect movement, we will impede the spread of the disease.”

California and Arizona have an advantage in the ACP-HLB fight that no other citrus-growing region in the world has had — time to prepare for the showdown.

Fight and detection preparation includes a wide variety of efforts including GPS-based insect trapping, delimitation, HLB checks on captured psyllids by the CRB laboratory in Riverside, and others.

A key to the ACP-HLB fight is ‘in the grove’ lookouts. Growers and pest control advisers routinely check groves for psyllids and suspicious-looking trees.

As a grower himself, Severns takes this responsibility personally.

“I have a responsibility on my farm to my neighbors, the industry, and to myself to be on a vigilant lookout for the pest and disease. HLB is a potential death sentence for this industry. Growers and packers — small and large — are equally engaged to report any suspected problems.”

Agricultural associations and government entities have proactive policies in place. The California-based Sunkist Growers Inc. citrus cooperative, which the Orange Cove - Sanger Citrus Association is a member, requires an orchard with a psyllid be treated with insecticide before the fruit is picked and moved to the packinghouse. Likewise, the California Department of Food and Agriculture (CDFA) will immediately remove every HLB-infected tree. No exceptions. CDFA carried this out when the HLB-infected tree was found in the L.A. area. Rapid tree removal reduces disease spread.

Severns urges citrus growers and homeowners to be pro-active on ACP and HLB. Suspicious-looking insects, trees, and fruit should be reported immediately to their county Agricultural Commissioner Office.

CDFA’s Report-A-Pest hotline phone number is (800) 491-1899.

cblake@farmpress.com