A plant disease that is fatal to citrus was detected a few days ago in Colton, prompting a 5-mile radius quarantine that affects at least four Redlands groves.

If untreated it could devastate citrus growers, said the California Department of Food and Agriculture during a public meeting held on Monday, Feb. 3, at the Redlands Council Chambers.

Representatives from the San Bernardino County Department of Agriculture/Weights and Measures were also present to discuss processes for growing, harvesting and moving citrus inside the quarantine boundary.

Nawal Sharma, manager for the quarantine response program at the California Department of Food and Agriculture, said that Huanglongbing (HLB), also known as the Citrus Greening Disease, has no cure and until scientists find the best way to treat it, homeowners with citrus trees and commercial growers should work together to minimize the effects.

It is hosted by a tiny insect, the Asian citrus psyllid, which can transfer the disease from tree to tree as the insect feeds on citrus leaves.  

The psyllid has been found in groves all over Southern California, including commercial groves. Just having the psyllid in the tree does not mean the tree is diseased, however. There is hope if the psyllid can be eradicated from backyards.

“If we don’t take care of it there is a risk of a wide area being impacted,” Sharma said.  Everybody has to participate in the effort to stop the spreading. Florida has lost nearly 50 percent of its citrus production due to HLB — that’s how serious this is.”

The Redlands groves affected are Palmetto Grove, Mountain View, Interstate 10 and the Gateway Grove, said representatives of Redlands’ Facilities and Community Services.

A commercial citrus grove is defined as any parcel with 25 or more citrus trees.  

Fruit harvested from city groves within the quarantine area can still be packed and sold but must undergo additional treatment.

The staff is in the process of assessing the fiscal impact to these groves, said the staff. Growers and haulers transport would have to file compliance agreements with the California Department of Food and Agriculture.

If growers are shipping fruit within the same contiguous HLB quarantine area they would have to spray and harvest, transport completely tarped or in a fully enclosed vehicle and complete a HLB pest risk mitigation form.

If they ship outside the HLB quarantine area or to a different quarantine area, they would have to follow the same rules in addition to wet wash or field clean by machine.

If growers are shipping to a packer or processor inside the quarantine area, they would have to transport completely tarped and complete a ACP-Free Declaration Form.

Under the guidelines, all fruit moved outside the HLB quarantine area may only be moved to a packing house or processor under compliance to receive HLB quarantine area fruit, said Sharma.

Manuel Martinez, general manager at Redlands Foothill Groves, one of the oldest and last operational packinghouse in San Bernardino County, said that HLB has been found in residential trees in the area and not in commercial groves.

However, for that to happen is just a matter of time since many commercial growers don’t spray as required, said Martinez.

“The product could be transported but there is an intense process. The quarantine means that all groves inside the area would have to follow the rules, would have to spray and wash the fruit on the field, which is difficult to do, it needs machinery, it costs money,” said Martinez.

“If a grower does not have the valid reports, we can’t take the product.”

Martinez said that people should be free of worries because the disease does not affect humans and because the product will be thoroughly processed before it reaches the stores. “It’s 100 percent safe,” he said.

Each year the packinghouse sells between 800,000 and 1 million 40-pound cartons of citrus throughout the United States, Canada and Asia. However, a rampant HLB could impact production.

According to the Citrus Research Board, established in 1968 under the California Marketing Act, as the mechanism enabling the state’s citrus producers to sponsor and support needed research, California produces approximately 80 percent of the nation’s fresh citrus and is the county’s main source of free-market oranges. California also supplies 87 percent of the nation’s lemons.

According to the city, for almost 75 years Redlands was at the heart of the largest navel orange producing region in the world, attracting people from all over the world from the late 1800s to the late 1950s.

In 1890, 1,000 railroad cars of navels were marketed. By 1904, over one million boxes were sent in more than 9,000 railroads cars from more than 30 packing houses.

Today in San Bernardino County, only one packinghouse remains to serve the needs of approximately 2,500 acres of citrus that remains in production in the area, including 16 citrus groves totaling 164 acres owned by the city.

HLB, in theory, is not only the most devastating disease of citrus in the world, but it also represents a threat to the few citrus groves that persist in the area.Sharma said scientists all over the world are working to find a cure.

Citrus threat

Jan. 6: 122 square miles were under quarantine in Riverside County and 139 square miles in San Bernardino County.

Jan. 24: The number increased to 134 square miles in Riverside County and to 178 square miles in San Bernardino County.

Monday, Feb. 3: Orange County was the most impacted by HLB with 1,303 trees infected, 452 in Los Angeles County, 26 in Riverside County and seven in San Bernardino County.