Aphid-sized insect threatens California’s citrus

By: Gloria Young Journal Staff Writer
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An insect that is ravaging citrus trees in Florida and has been found in Southern California hasn’t reached Northern California yet. And local growers want to make sure it doesn’t. The Asian citrus psyllid carries Huanglongbing — known as HLB, or yellow leaf disease — which is deadly to citrus trees. “The insect carries the vector from tree to tree,” explained Scott Jordan, vice president of the Mountain Mandarin Growers Association. “It will infect the tree. Then another bug comes along and carries the infestation to another tree. It is kind of like pollination, only in a very bad way.” Once the disease strikes, it doesn’t take long to do the damage. “The problem is that the disease kills the trees within about five years, and within about two years, the fruit will be inedible,” said Cindy Fake, horticulture and small farms adviser with the UC Davis Cooperative Extension office in Auburn. “The insect itself will damage the trees. But the disease will kill the trees.” The tiny insect is similar to an aphid in size, she said. Placer County mandarin growers have joined statewide efforts to keep out the psyllid and HLB. A campaign that includes TV and radio ads is focused on educating homeowners about the threat. “The concern is that people would get the tree from grandma in Los Angeles as a Christmas gift, then drive back up after Christmas with the tree that hasn’t gone through any inspection process,“ Jordan said. “Then they get it home and plant it in the ground. The concern is that the tree from grandma’s house was infected and is now carrying this small bug that is not very visible to the naked eye.” The message to residents traveling outside the area is not to bring back citrus trees. “When I buy trees in the Central Valley to plant here, they have to be inspected by the Agricultural Commission there and then inspected here or in the county where it will be,” Jordan said. “Paperwork must follow the tree. It is a very strategically planned way to mitigate these problems.” But for residential growers, there’s no easy detection method. “Unless you’re an entomologist, don’t think you can interpret the findings and think it is OK,” Jordan said. “Just don’t transport citrus.” Educating people to be on the lookout for the insect is an important step. The National Academy of Sciences estimates that 100 million trees in 40 countries are affected by HLB. The psyllid and HLB have devastated citrus production in Asia, India, parts of the Middle East and South and Central America. Florida is losing about 10 to 12 percent of citrus production annually, according to a UC Davis Cooperative Extension press release. This is the second or third year local growers have been aware of the problem. “But it has moved fairly rapidly in the last couple of years, from Florida through Texas and into Mexico and now into Southern California,” Jordan said. Jordan has about 450 mandarin trees. “We have one of the youngest mandarin orchards (in Placer County,” he said. “We planted six or seven years ago and (the trees) are starting to produce now.” In Southern California, the majority of the infestations have been found in residential backyards, Jordan said. However, there’s no problem buying citrus trees locally. High Ranch Nursery in Loomis is a wholesaler, providing trees and plants to nurseries all over Northern California. “We sell a lot of citrus, including mandarins,” sales manager Roger Snell said. “If you’re located in Loomis, you have to sell mandarin trees.” Most of High Ranch’s citrus is grown on site. “That’s the way it is with all the (area wholesale) nurseries,” Snell said. “That is because of another disease that was found on citrus years and years ago.” Reach Gloria Young at