Symptomatic leaf blotches for Huanglongbing

Huanglongbing disease is characterized by asymmetrical yellowing on citrus leaves. The disease is confirmed through scientific testing recognized and approved by the USDA.

Five new cases of Huanglongbing reported in California

Huanglongbing spreading in California's San Gabriel Valley Nine trees confirmed and destroyed 30 nurseries impacted by quarantine

Five more cases of Huanglongbing, the deadly citrus disease for which there is no cure, have been were confirmed in San Gabriel, Calif.

The confirmation by the California Department of Food and Agriculture (CDFA) brings to nine the total of HLB-positive trees discovered by state regulators since 2012.

Eight of those were confirmed within the past month in San Gabriel. The first was a grafted lemon and pomelo tree in Hacienda Heights.

Both locations are within about 15 miles of each other east of downtown Los Angeles.

The five latest finds were on three properties, according to the CDFA. One location had three citrus trees test positive for the fatal disease. Two other properties had one tree each on them. So far, the infected trees include a kumquat, lime, mandarin and calamondin.

The discoveries do not change the existing HLB quarantine in the San Gabriel Valley, which was recently expanded after the initial finds were confirmed. The quarantine now covers 180 square miles and takes in numerous cities, including Pasadena, Alhambra, East Los Angeles, El Monte, San Gabriel, Whittier, West Covina and Hacienda Heights.

The quarantine impacts 30 nurseries with citrus nursery stock. Over 8,000 citrus plants were placed on a quarantine hold by state officials.

Of the nurseries impacted, 29 opted to have the plants destroyed. The remaining nursery opted to build an approved structure for the 111 nursery plants it has in stock. That nursery had until Aug. 9 to build the structure and comply with U.S. Department of Agriculture requirements, which include sequestering the plants for a period of time and monitoring them for the disease.

Huanglongbing, otherwise known as citrus greening, is caused by a bacteria spread by the Asian citrus psyllid (ACP), a pest that is now widespread across southern California and has been found as far north as San Jose.

The disease is particularly troublesome to commercial citrus growers as it has decimated Florida citrus groves since it was discovered there in 2005. The ACP is the only known vector for HLB, which is why California has made a concerted effort to combat the pest.

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