More than 100 invasive insects carrying a devastating disease that can kill citrus trees have been found in southern San Luis Obispo County this year — triple the number found in 2017.
An Asian citrus psyllid is no bigger than a grain of rice and carries huanglongbing (HLB), a bacterial disease that's transmitted to healthy trees by the insect after it feeds on infected plant tissue, according to the California Department of Food and Agriculture.
Karen Lowerison, deputy county agricultural commissioner, said about 100 adult psyllids and 39 nymphs have been located in the Nipomo area in 2018.
"We're being really proactive with this detection program," Lowerison said. "We have about 2,000 traps set up around the county, mostly in the South County."
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Though the insects have been contained to the Nipomo area, Lowerison said Asian citrus psyllid infestation is always considered a significant threat.
There are about 2,000 acres of citrus trees in San Luis Obispo County, she said, which were valued at $17 million in 2017.
Lowerison said the quickest way to spread insects and disease is by importing trees from outside the area. She encouraged residents to buy from local licensed nurseries and avoid moving citrus trees, fruit or cuttings between counties and states.
In a 2017 Tribune article, Leonard Cicerello, a UCCE Master Gardener, said trees should be inspected regularly for any signs of feeding damage and psyllids.
"Look for new flush that's twisted," Cicerello said. "Look for eggs, nymphs and waxy tubules among that twisted new growth. Look for feeding adults that sit at a 45-degree angle with their head down and abdomen up."
Agriculture officials have been proactive in hanging yellow sticky traps on citrus trees in urban areas and in commercial orchards, and they check regularly for signs of the pest. They also inspect flushes of new growth, where the psyllid prefers to go, according to Cicerello.
If you have a citrus tree in your yard or commercial landscape, you can help. Volunteer to have a sticky trap placed in your tree by calling the county Ag Commissioner's office at 805-781-5910 and sign up for the trapping program.
To request a trap, visit the San Luis Obispo County Department of Agriculture website, fill out the "Approval to trap in my yard" form and return it to one of the county offices in Arroyo Grande, San Luis Obispo and Templeton.