Kevin Severns’ message to citrus growers could not have been more well-timed.

The Sept. 23 citrus grower meeting in Dinuba, Calif., where Severns spoke on best management practices growers can voluntarily employ had barely come to a close when Tulare County Agricultural Commissioner Marilyn Kinoshita announced to an audience of about 300 growers, packers and other citrus industry people that another Asian citrus psyllid (ACP) had just been discovered on a trap, this time in the Exeter area of Tulare County’s citrus growing region.

The Dinuba meeting was the second of two large grower meetings held in Tulare County during the summer months to address a growing number of psyllid finds in the county. Its tone was slightly more somber than the first given that ag officials were now using the term “infestation” in their talk to growers and packers: this because several small citrus trees in a residential yard in Dinuba had an estimated 400-500 adult psyllids and nymphs in them.

Growers and packers were also told about regulatory compliance agreements they must enter into because of the quarantine restrictions.

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Most troubling for officials is that the yellow sticky traps used to sample bug populations appear to be ineffective at capturing a true representation of psyllid populations in the region.

While three backyard citrus trees in Dinuba were infested with adult psyllids and their nymphs, the two sticky-card traps located on either side of the infested property had managed to capture only one or two psyllids on each trap. It was only after careful inspection of a yard by a keen-eyed ag inspector that the infestation was discovered.

“What concerns us is that these bugs apparently sat in that yard a long time and nobody noticed them,” said Elizabeth Grafton-Cardwell, a research entomologist with the University of California and an expert on the ACP.

“What this means is the yellow sticky cards are not effective in picking up the psyllids,” she continued. “That’s really discouraging.”

The one good bit of news from the Dinuba discovery was that adult psyllids were able to be collected and tested for Huanglongbing (HLB). Those tests came back negative.

While discouraging, the Dinuba psyllid discoveries illustrates Severns’ point that growers and residents play a key role in slowing the spread of the ACP.

“What we’re talking about is not moving the bug from one place to another,” Severns said.

Severns' many roles

Severns wears several hats. He is a citrus grower, general manager of the Orange Cove-Sanger Citrus Association, secretary/treasurer of the California Citrus Pest and Disease Prevention Committee, vice chairman of the California Citrus Mutual and he sits on the Sunkist board of directors. The packing operation Severns manages processes and ships about 1.7 million cartons of navel oranges, 700,000 cartons of Valencia oranges, 50,000-70,000 cartons of Minneola tangelos and about 50,000 cartons of Cara Cara oranges each year.

Severns’ matter-of-fact tone of voice was urgent, direct and passionate.

He ticked off a list of practical steps and best management practices growers, pickers, packers and others can take in slowing the ACP spread in California.

“We need to be vigilant,” he said.

Practically speaking, Severns is promoting the idea of cleaning every piece of equipment that leaves a citrus grove before leaving that grove. While not talking about completely washing everything, he is talking about making sure things like pickups, four-wheelers, field restrooms, bins, trailers, ladders, forklifts, trimming equipment and the bags used by farmworkers when picking fruit need to be cleaned of leaf and stem materials and inspected for psyllids.

“I’m not just talking about the quarantine areas, but everywhere,” Severns said.

He also recommends that harvest crew bosses collect all bags and other materials used by picking crews and be responsible for ensuring the bags are cleaned of all vegetative materials and bugs prior to moving to the next grove.

As a packer, Severns has seen citrus bins arrive at the packing shed with leaves, stems and other tree materials in them.

“That does not need to be hauled into the packing house with that load,” he said.

Severns is talking about going beyond regulatory requirements aimed at slowing the spread of the ACP. Those requirements include spraying loads prior to leaving the field and tarping the trucks hauling the loaded bins to the packing house.

“We need to broaden our scope to include anyone and everyone who enters a citrus grove,” Severns said.

Practical steps include watching for tree materials that can become snagged on pickups and equipment in the field. Those materials need to be removed in the field and not transported out of the grove. Ladder trailers, field restrooms (inside and out), and the various other pieces of equipment must be inspected and cleaned of all vegetative materials before leaving the orchard, he said.

That includes educating harvest crews about the need to keep their car windows closed and even check their clothing for psyllids prior to leaving the grove.

Buying time through diligence

Severns said grower acceptance of the ideas he shared at the Dinuba meeting seem to be positive.

“Growers know what we’re up against,” Severns said.

What Severns is promoting are over-and-above measures citrus growers and others involved in the industry should do in addition to government mandated practices.

“We need to buy ourselves some time with this bug,” Severns said. “Everywhere this bug has been discovered we’ve eventually seen HLB. It’s important that we slow its movement long enough to buy ourselves time to address HLB.”

Severns said not all is doom-and-gloom. The association he manages is in the midst of an expansion project to add significant cold storage capacity and local growers are still planting new trees.

“You don’t do things like that unless you remain optimistic about the industry,” he said.

Since the Dinuba citrus grower meeting, an additional quarantine zone was added in Tulare County to reflect Kinoshita’s report of a psyllid discovery near Exeter. That quarantine encompasses 86 square miles and takes in all of Exeter and most of the communities of Lindsay to the south and Farmersville to the northwest. This is in addition to the 90-plus square miles in the Dinuba area and the 178 square-mile area surrounding Porterville.

According to Kinoshita, 55 of Tulare County’s 62 citrus packing houses are now within one of three quarantine zones.

The Dinuba quarantine zone, which already stretched into neighboring Fresno County, was expanded further into Fresno County in early October as an ACP was discovered on a trap in Fresno County. Local Ag officials were unable to release the new quarantine boundaries as of press time.

Quarantine information and regulatory compliance agreement forms related to the movement of citrus in quarantine zones can be found online at http://www.cdfa.ca.gov/plant/PE/InteriorExclusion/acp_quarantine_sjv.html.

Citrus Pest and Disease Prevention Program grower liaisons can be contacted at:

For more information on the ACP quarantines and about regulatory compliance issues, contact the ACP Project Office in Visalia at 345 East Tulare Ave., Suite M, Visalia, CA 93277, or at (559) 636-7410.

 

tfitchette@farmpress.com

 

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