Over 20 trees added to state HLB List
So far Central Valley is safe
As the number of citrus trees testing positive for the industry decimating huanglongbing disease rises in the state, local officials aggressively work with growers and homeowners to keep it at bay.
Diaphorina citri, also known as the Asian citrus psyllid, is not much bigger than a grain of rice, but is known to carry huanglongbing disease, or HLB, which has impacted citrus industries all over the nation in a big way.
According to a report by Agnet West Radio Network in Fresno County, over 20 new trees in Southern California have been confirmed Hlb-positive, raising the total number of trees with the dangerous citrus disease found in the state to around 100.
HLB was recently found as far north as Riverside County in residential citrus trees.
Even though the Asian citrus psyllid is known to have been in the Central Valley, Alyssa Houtby, the director of government affairs for California Citrus Mutual, said there hasn’t been a find recently.
“We have found it [Asian citrus psyllid] here in the past, but the disease [HLB], we have not found here in the Central Valley,” Houtby said.
When a tree is infected with HLB, which is also known as citrus greening disease and yellow dragon disease, among other names, Houtby said it usually takes about five years to die. She said the Asian citrus psyllid will usually feed off of a tree, taking up the bacteria, and then fly off and feed on another tree while also injecting bacteria into it.
“That is how this disease is spread so rapidly and why controlling the Asian citrus psyllid is so important to stopping the disease from spreading,” Houtby said.
Once a tree is infected, Houtby said the disease, which can’t be cured, restricts a tree’s ability to take up nutrients. The only option, Houtby said, is to remove the tree.
When removing a Hlb-infected tree, Houtby said the CDFA first treats the
tree for the Asian citrus psyllid to make sure that any insect that is on the tree is killed. She said the CDFA will then remove the entire tree, including the root ball, double bag it and send it to a landfill.
Houtby added that the CDFA also treats every citrus tree within an 800-meter radius of the infected tree for the Asian citrus psyllid.
“As a means to keep the disease from spreading, we make a concerted effort in that 800-meter delimitation area to eradicate the Asian citrus psyllid as best as possible,” Houtby said.
To determine if a tree has been infected with HLB, Houtby said the only way to know for sure is through a lab analysis, which she said is done by the CDFA.
Before having it analyzed in a lab, Houtby said people can get a good idea if their tree has HLB if it starts to show signs of yellowing leaves. As the disease spreads throughout the tree, Houtby said it will stop producing fruit or will produce fruit that is bitter and always stays green.
“That symptom [greening] is in the later stages of infection,” Houtby said, adding that the first symptom someone would see in their tree is yellowing of leaves.
Nevertheless, Houtby said “to absolutely, 100 percent confirm that a tree is infected it needs to be sampled by CDFA and those samples need to be confirmed in a lab.”
If a homeowner or a grower is concerned that their tree might be infected, Houtby said they can contact their local county agriculture commissioner who will, with CDFA, send somebody out to inspect the tree.
“If a homeowner is notified by the Department of Food and Agriculture that their tree is infected, we ask that they cooperate with ag officials, allow us to remove the infected tree, and allow us to do treatments
of any other citrus trees on the property,” Houtby said. “Similarly, if a homeowner is asked to have a trap placed on their tree by the county, we ask that they cooperate and allow us to do that because that is how we find the insect and how we locate infected trees and stop the problem before it expands anymore.”
Stopping the problem while still small, Houtby said, will help prevent California’s citrus industry from being ravaged as Florida’s industry has.
Houtby said the value of the Florida citrus industry is now less than that of the California industry when, at one point in time, she said it was double the size.
“In the last decade, they’ve [Florida citrus industry] lost about 75 percent of their production,” Houtby said. “There’s definitely a concern and a concerted effort to make sure that does not happen here in California, which is why we, as an industry, assess ourselves and implement a comprehensive program that involves looking for the disease, sampling trees, pulling out infected trees and doing residential treatment.”
Houtby said residents and farmers can also do their part in helping to prevent the Asian citrus psyllid from spreading the HLB disease. The most effective approach, Houtby said, is with insecticide treatments.
She said an overthe-counter product at Lowe’s or Home Depot will do the job.
“It is a very simple process of just spraying the base of a tree,” Houtby said. “It is called a systemic insecticide and the tree takes it up and it acts as a defense mechanism against the insect so when the insect goes to feed on the tree it takes up that insecticide and it kills the insect.”
For more information regarding the Asian citrus psyllid and the HLB disease, Houtby said residents and farmers can call 1-800-491-1899 or visit www.californiacitrusthreat.org.