Jerry Bishop, a dog trainer and handler with Florida-based F1-K9, scouts a Ventura County, Calif., lemon grove for HLB-causing bacteria with Bello, a springer spaniel. A number of growers and researchers believe specially trained dogs may be a viable early-detection tool for the devastating citrus disease that threatens the state's citrus industry. ( Courtesy Farm Bureau of Ventura County )

The citrus industry in California’s Ventura County is going to the dogs.

Through a partnership with the Ventura County ACP-HLB Task Force, a handful of growers availed themselves this summer to the services of F1-K9, a Smyrna Beach, Fla.-based firm that provides dogs that can detect the presence of bacteria that cause citrus diseases — specifically huanglongbing, also known as HLB.

Four dogs and two handlers scouted about 3,500 trees during a four-day period in late July and early August, said John Krist, CEO of the Ventura County Farm Bureau.
“They alerted on 211 trees,” he said.

Growers, acting out of an abundance of caution, removed most of those trees.

Those that were not removed will be monitored to see if and when they develop symptoms of HLB.

Growers turned to the specially trained dogs because they are said to be effective at early detection.

“The dogs can detect the presence of the bacteria very, very early in the infection stage — perhaps three or four years before the standard regulatory tests using PCR — Polymerase Chain Reaction — technology,” Krist said.

F1-K9 has 21 dogs that can detect the presence of diseases like HLB, citrus canker and plum pox, said Bill Schneider, the company’s chief research scientist.

Dogs currently are training to detect viruses associated with squash and tomatoes.

Proper training takes about four months. 

Dogs can sniff an entire tree in one quick pass, and they are 95% to 99% effective, he said.

Leslie Leavens, an owner and vice president of finance and operations for Leavens Ranches, Santa Paula, Calif., and chairwoman of the Ventura County ACP-HLB Task Force, is one of the growers whose ranches were checked out by the dogs.

“I think this is an absolutely critical tool for growers to be using in areas where there may be HLB and to help get the infection out years before it is detectable by PCR,” she said.

To date, the effectiveness of using dogs to detect HLB has not been validated by the U.S. Department of Agriculture. The PCR method is the only regulatory tool officially approved for detecting the disease. But Leavens has faith in the canines.

“The protocol for sampling for PCR is pretty rigorous, but there’s still a real element of chance involved,” she said.

“By the time the disease is detectable by PCR, it’s just too late for commercial citrus growers.”

Neil McRoberts, associate professor of plant pathology at the University of California, Davis, and Western region director of the USDA-funded National Plant Diagnostic Network, also has confidence in the dogs.

No diagnostic test is 100% accurate, McRoberts said, “But (dogs) are very, very accurate in comparison with other technologies that are available.”

Other approaches have been examined, he said, but none are ready for wide-scale implementation.

The Asian citrus psyllid that can spread HLB was detected in Ventura County about a decade ago, Krist said. So far, there have been no confirmed cases.

“But we had suspicions because of our proximity to urban Southern California, where HLB has been confirmed, and all the transportation corridors that run through our citrus production areas in the county,” he said.

Plans call for deploying a team of dogs in the county permanently starting early next year.

“We’re trying to build sort of a picture of where the bacteria may be distributed in Ventura County,” Krist said.

“If we’re catching it as early as we think we are and promptly removing those potential sources of infection, we’re very excited about that opportunity,” Krist said.

“We know that if we just wait around until random sampling turns up confirmation ... it’s probably going to be too late.”


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