The Asian citrus psyllid can transmit the citrus greening bacteria from tree to tree as it feeds.
The Asian citrus psyllid can transmit the citrus greening bacteria from tree to tree as it feeds.

The discovery of a single citrus greening-infected tree in a Los Angeles County neighborhood is extremely disappointing, says a citrus industry leader.

The California Department of Food and Agriculture confirmed that an Asian citrus psyllid sample and plant material taken from a Hacienda Heights lemon/pummelo tree were positive for citrus greeening, also known as huanglongbing or HLB, according to a news release.

"The department has done an excellent job of briefing the industry about the discovery of that single tree in Hacienda Heights," said Joel Nelsen, president of Exeter-based California Citrus Mutual. "It's just extremely disappointing."

So far, tests on adjacent trees and additional psyllids have come back negative, he said.

The tree didn't show symptoms, and the psyllid was the first thing that surveyors noticed.

Asian citrus psyllids transmit the greening bacteria from tree to tree as they feed.

"We'll see if the system and the program work as good as we think they will," he said about the industry, state and U.S. Department of Agriculture's greening detection and eradication efforts.

The good news, Nelsen said, is so far homeowners nearby have been willing to treat their citrus trees with the recommended insecticides to control the Asian citrus psyllid.

The infected tree has been removed and destroyed.

The tree originated from a church exchange or sale some time ago.

Nelsen said the USDA is conducting an investigation into the tree's origin.

Even before the citrus psyllid was found in California, the pest and the greening disease it carries have been a hot topic for discussion among the industry, he said.

At mutual's recent Citrus Showcase, Nelsen said 600 to 700 growers attended to hear the latest about the state's greening detection and eradication program.

"We didn't know it was going to be utilized so quickly," he said.

The citrus greening bacteria is harmless to humans, but it can stunt, weaken and even kill citrus trees.