By Mark Muckenfuss
Workers with the California Department of Food and Agriculture are methodically checking what are likely hundreds of citrus trees in a mostly residential area north of the 60/91/215 freeway interchange in Riverside for signs of a deadly disease.
Huanglongbing, or citrus greening, is a bacterial disease that wiped out much of Florida’s citrus industry in the past decade, was positively identified in a grapefruit tree near Chicago Avenue and Marlborough Street last week. The tree was removed from the property.
Since then, agricultural inspectors have been canvassing an area within an 800-meter-radius of the infected tree.
“We’re doing a house-to-house survey and checking every tree,” said Yenny Melgoza, a pest-prevention assistant. “We started the survey the day we got the positive (results on the) tree.”
Temperatures that have pushed beyond 100 degrees and some heavy thunderstorms have not stopped the work. Melgoza said she doesn’t know how long it will take the 17 workers the state has deployed to finish the testing. There is no count yet on the citrus trees in the test area.
About 20 leaves are being collected from each tree, with a focus on those that might show symptoms of the disease.
“I’m just looking for any type of leaves that have any kind of yellow on them,” said Maritza Paredes, a technician who is not only collecting leaves, but any Asian citrus psyllids she might find on a tree.
Huanglongbing is transmitted to citrus plants by a tiny insect, the Asian citrus psyllid. Not all psyllids carry the bacteria, but they are the only known insect that serves as a vector for it. Symptoms of the disease may not show up for a couple of years, but citrus greening disease usually kills a tree within three to five years.
The fruit of infected trees doesn’t ripen properly. Fruit is green and misshapen and has a bitter taste. Leaves become mottled and misshapen.
Melgoza said patchy yellowing of the leaves is usually asymmetrical. She singles out a leaf on a tree in the yard of Charlie Glick, where she and Paredes are working. While the leaf is mottled, the yellow and green patches on either side of the leaf’s midline are about the same. With HLB, she said, the patches are more random.
Officials have been expecting the disease for some time.
The Asian citrus psyllid arrived in California in 2008 and soon moved into the Inland Empire. The first tree infected with huanglongbing was found in Hacienda Heights in 2012. Since then, trees have been identified in San Gabriel, Cerritos and, in May, La Habra.
The disease has infected about 75 percent of citrus trees in Florida, resulting in more than $4 billion in lost citrus. More than 26 million citrus trees have been lost in Brazil. Texas growers also are battling the disease.
Glick, 70, said he has been keeping track of the progress of the disease. He said he won’t be heartbroken if his six small citrus trees are found to be infected and have to be removed, but he worries about the bigger picture.
“It is very concerning,” he said. “I just hope we can keep our California oranges. What would the Orange Blossom Festival be without oranges?”