Courtesy Agricultural Research ServiceThe California Department of Food and Agriculture has enacted two new quarantines in the state’s main Central Valley citrus production area to try to halt the spread of Asian citrus psyllid.
A 90-square-mile quarantine around Dinuba and an 88-square-mile one around Wasco join an existing 178-square-mile quarantine in Porterville, said Steve Lyle, director of public affairs in Sacramento.
But fighting this pest is more than just establishing restrictions and spraying groves, Kevin Severns, general manager of the Orange Cove-Sanger Citrus Association, said he told attendees at a Sept. 23 grower meeting in Dinuba.
“I termed it a common-sense solution to not moving the psyllid,” he said. “What it amounts to is paying attention to everything they do out in the field, not just as it relates to harvest crews and whole fruit. It includes equipment that comes in from the field and not just field bins and trucks. They need to make sure nothing is carrying Asian citrus psyllid around.”
The concern with psyllids is they not only feed on citrus trees, weakening them, but they can also carry citrus greening disease, also known as huanglongbing or HLB. Although harmless to humans and other animals, greening can weaken and kill citrus trees. There is no known cure.
Greening is established in Florida, but so far, only one positive has been found in California and that was in a residential citrus tree in Hacienda Heights, Los Angeles County.
Severns said farm labor contractors, packinghouse managers and everybody else in the citrus industry need to impress upon employees the role they play minimizing the pest’s spread.
“This is what we keep hearing from Florida,” said Severns, who has traveled to Florida twice to meet growers. “If you control the psyllid, you can control the spread of HLB.”
The Dinuba quarantine was prompted after numerous psyllids were found in a residential citrus tree earlier this month.
Several thousand acres of citrus are within the restricted zone, which is roughly in a 5-mile radius of the finds, said Bob Blakely, director of industry relations for Exeter-based California Citrus Mutual.
Under the quarantine, all host plants within 800 meters of the find will be treated with an approve insecticide. In Dinuba, that involves at least 562 residential properties that the state will spray, with homeowners’ permission.
In Wasco, a lone psyllid was found on a residential tree, and little if any commercial citrus is within the quarantine, Lyle said.
State and federal surveyors have not found additional psyllids in either case, he said.
Growers in quarantined areas have the option of removing all stems and leaves before leaving the area or treating with an approved insecticide and harvesting within seven days.
Blakely said he expected most growers will opt for sprays because of the labor involved in removing plant material.
“There’s going to be certain additional steps and cost involved with these additional sprays,” he said. “And there are scheduling issues, but it’s what needs to be done as far as trying to stop this pest.”
Many growers also will be looking at using insecticides allowed against psyllids when they treat for other pests in case psyllids are in groves at undetectable levels.
“Even if they haven’t seen the psyllid, it’s a precaution to keep populations from becoming established,” Blakely said.
Growers also are being encouraged to work with neighbors and take a coordinated approach to treatments. That way, psyllids can’t jump from a treated grove to an untreated grove to seek refuge.
“If they’re going to be spraying, it makes sense to talk to each other and time their sprays so they cover a large area at one time,” he said.
Citrus nurseries within the quarantine zones are prohibited from moving plant material to outside areas unless it comes from a U.S. Department of Agriculture-approved structure.
The quarantines will remain in place for two years, barring additional psyllid detections, Lyle said.