Around Ramona and Loma Linda, a citrus tree can now have a second identity: the tree in the ground, and the regulated plant part that cannot simply be loaded onto a truck. For nurseries and growers in those communities and nearby areas, the boundary on a map has become part of the crop’s paperwork.
The U.S. Department of Agriculture’s Animal and Plant Health Inspection Service expanded California’s federal quarantine for citrus greening, also called Huanglongbing, with the change taking effect immediately. The action adds federal force to restrictions already established inside California, particularly around Ramona, Loma Linda and surrounding areas.
A Tree Disease With a Shipping Problem
Citrus greening is caused by the bacterium Candidatus Liberibacter asiaticus. Infected trees produce fruit that can be lopsided and bitter, then decline. The disease is spread by the Asian citrus psyllid, a small sap-feeding insect that has settled into much of Southern California; there is no cure for an infected tree, according to UC Agriculture and Natural Resources.
That biology is why the quarantine reaches beyond visibly sick trees. Nursery citrus, budwood, cuttings and other plant parts can carry risk even when the leaves look like leaves and the fruit looks like fruit. Moving them is the part of the operation now most likely to collide with the regulatory boundary.
The federal expansion follows California’s intrastate quarantine actions of March 2 and March 6, 2026. In practical terms, APHIS is aligning the federal quarantine with lines CDFA had already drawn within the state, rather than creating an unrelated citrus rule.
The Boundary Reaches the Nursery Bench
For a citrus nursery, the affected material may be small enough to fit in one hand but consequential enough to halt a load: a young tree, a graft, a cutting or another piece of living plant tissue. Growers near the expanded area face restrictions on moving those materials, so a shipment planned before the change may no longer travel on its original route.
The quarantine arrives as California’s citrus map is already being redrawn in response to new detections. CDFA and USDA confirmed HLB in one residential tree in Calexico in August, the first reported detection in Imperial County, and opened a county quarantine area with local and federal agencies involved. Residential trees are often where the disease first appears in a neighborhood; commercial growers inherit the movement rules that follow.
The next decision point is any planned movement of citrus from a property in or near the expanded zone. Before loading nursery stock or plant parts, operations will need to check the current CDFA and APHIS requirements for the origin, destination and type of material. A truck that is legal at the orchard gate can become illegal at the county line, which is an especially unromantic way for a citrus schedule to fail.