Asian Citrus Psyllids Continue Hitchhiking Entrance into the South Valley

The small Asian Citrus Psyllid (ACP) remains of big concern to local citrus growers, as well as the California citrus industry.

First detected in California in the fall of 2008, the first psyllid was found in Southern California, believed to have hitchhiked its way up from Mexico. Areas south of the San Joaquin Valley have had “full infestations in San Diego, Imperial, Riverside – essentially everything south of the Grapevine,” said Tulare County Ag Commissioner Marilyn Kinoshita.

“In San Bernardino County they have the yellow panel trap and they can find 500 psyllids on it, whereas we’re finding one [per trap],” she added.

But, the number of individual finds is increasing, with seven finds from the end of March through the end of April, within the county, which is bad news. The good news is that they are not infestations and only a single, or a few psyllids were trapped. The even better news is that all finds remain negative for Huanglongbing (HLB) disease.

There are continued and growing concerns, said Bob Blakely, vice president of California Citrus Mutual.

“We have done [and are doing] everything we can to suppress more psyllids from coming up from Southern California,” he said. “But they keep popping up in residential areas.”

Psyllids negative for the disease can still cause problems, especially when in full infestation mode for a tree or a group of trees, but diseased psyllids would create devastating effects to the citrus industry.

“There’s so many different ways that we can get ACP finds here – because we’re the Number One citrus county in the state, the majority of the packing sheds are here, and almost all the juice plants are here,” Kinoshita said. “We get fruit from Mexico, the desert – Arizona, it just all flows up here plus hitchhikers.

“Even if you had juice fruit that was washed and waxed and sent from a packing shed – the truck driver, they usually leave their windows open when their waiting,” she said, and a psyllid could fly in the window and fly out upon arrival to Tulare County.

People go to Disneyland and get in and out of their vehicles, she added.

“You’ve got tons of ways. The hedgers and toppers may not get all the leaf trash and they move around different parts of the state. The picking crews – there is so much training about them emptying out their bags on site before they move onto the next block, but even they move around where ever the jobs are, where ever their labor contractor gets them work.

“Then there’s the underground movement – fruit peddlers – they might have a list of growers who instead of moving that third picking through the packing shed and paying packing costs when the fruit is a little bit marginal – they’ll strip the grove off and with a flatbed of bins, they might take to a flea market. And some of the movement is down to the LA markets, so they are moving back and forth – they may live here but they’re going down there to sell and then they come home.”

There have been a couple of hot spots in the area in recent years.

A particular mandarin tree in Dinuba was found in 2013 where a couple hundred psyllids were collected and a lot more involved in this one tree, which was full of them, Kinoshita said.

In 2014, a lemon tree and a mandarin tree on one property had numerous adult and nymph psyllids found.

But these have been the only infestations found locally, she said.

More individual and recent incidents include the Sunkist-Ventura Coastal juice plant in Tipton, where individual psyllids were found on the six trees of the property. The trees were immediately treated and recently removed and destroyed, Kinoshita said.

All of Tulare County is in quarantine for ACP. When an individual is found, there is a phone-tree where growers call each other relevant to the find to indicate a particular area is in need of treatment – just in case.

“Pesticide application effective on psyllids needs to be done within a two-week period [of the find], and in as short a time period as possible. Growers have to follow all pesticide regulations – we’re the monitor of that,” Kinoshita said.

“In city finds – that is a 400-meter circle [that needs to be treated] – the California Department of Food and Ag has spray crews that make contact with the homeowners and provide them information. There is also a public meeting,” she said.

Recently there were a multitude of finds all within the Tulare area – the subdivision just north of Paige and Highway 99 had a find, about one-quarter mile north of that had one, plus Bardsley, east of Laspina, and Prosperity, east of Mooney, she said.

All of these areas had a combined meeting two weeks ago, she said, and only six people attended.

“Our local residents understand agriculture here,” Kinoshita said. “We have very few problems, very few refusals unlike Santa Barbara County, or San Luis Obispo county where you have people with million dollar homes, and attorneys and aren’t afraid to use them. And, they have some misconceptions about pesticide applications, because those same type of people think that with organic produce there is not pesticides used, and that is far from the truth.”

The CDFA sprayers, are very professional, she said. They cover pet water dishes, koi ponds, fountains and sensitive plants and they’re only treating the citrus trees.

In 2015, two finds of HLB were found in Southern California – the first was in a grafted lemon and pomelo tree in Hacienda Heights, and the second in a residential area of the San Gabriel Mountains on some clippings from a kumquat tree with subsequent finds in the neighborhood.

HLB-positive finds result in treatment and mandatory take down of the trees involved.

The bacterial HLB is fatal to citrus trees and would be fatal to the citrus industry if spread. Many California counties are under quarantine for the disease with continued proactive organization to prevent it.

“Imagine throwing a pebble into a pond,” Blakely said. “The pebble is the first psyllid with HLB. It ripples with more psyllids until it spreads all the way across the pond. That is what we’re afraid of.”

Signs of HLB include irregular, mottled yellowing of leaves, and lopsided, small and bitter fruit. There is no cure for trees that become infested. It is not harmful to humans or animals.

While all psyllid findings in the South Valley have tested negative, any of those hitchhikers could be positive, Kinoshita said.

“This could be affect anyone, not just the growers,” she said.

Local residents are urged to follow some simple steps:

  • Don’t move citrus plants, plant materials or fruit in or out of quarantine areas, or in or out of the state or country.
  • Inspect your own citrus trees monthly and when tending to your trees, for signs of HLB disease.
  • Only purchase and plant trees from licensed, reputable California nurseries.
  • Use only registered budwood to graft trees that come with source documentation.
  • Dry out or double bag plant clipping material before disposing of them.
  • Talk with your local nurseryman about applications that you can use to stop possible psyllids on your trees.

So far, we’ve been lucky,” Kinoshita said.

“It happened much more quickly in Florida, because they weren’t prepared for it,” Blakely said.

The hope is that through all the preventative measures, it will not be as disastrous here.

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