Ensuring clean plant material

The state of California has strict regulations and methods in place to ensure that citrus trees are tested for pathogens to verify that they are free of disease before they are sold. However, the general public does not always understand the importance of these regulations, and people sometimes unknowingly bring diseased plant material (citrus and other hosts of ACP-HLB) into California and graft their own trees.

Citrus Clonal Protection Program

The UC Citrus Clonal Protection Program (CCPP), housed at UC Riverside, is the gatekeeper of California citrus. CCPP is one of the three programs in the nation authorized to import citrus budwood from overseas and is charged by the state to conduct disease diagnosis, pathogen elimination, and the distribution of true-to-type, clean citrus propagative material of fruit and rootstock varieties to nurseries and private individuals. The CCPP is directed by Georgios Vidalakis, UC Cooperative Extension specialist in the Department of Plant Pathology and Microbiology at UC Riverside.

 “Unforbidden” fruits

Scientists at UC Riverside are developing a legal source of plant material for popular non-citrus ACP hosts, such as bael tree, a native food plant of India also used for traditional medicine, and Indian curry leaf, a food flavoring. The program—run by Tracy Kahn, principal museum scientist, and David Karp, associate in the Agricultural Experiment Station, in the UC Riverside Department of Botany and Plant Sciences—will provide clients with clean plants, reducing the incentive for smuggling plants and plant material into California that potentially harbor ACP or HLB. Kahn has also joined forces with the U.S. Department of Agriculture to assemble the only collection in California that includes all the major host plants of ACP and HLB—all varieties of citrus and closely related plants in the family Rutaceae.