At the time of this writing we appear to be sailing through a fairly warm winter. As citrus growers know, though, this situation can change rapidly. The only thing on the visible horizon throwing a chill over this season so far has been the discovery of several Asian citrus psyllids in Tulare County. Advance planning and preparation, largely instigated and initially conducted by your citrus commodity board ‐ The California Citrus Research Board – has made the southern San Joaquin Valley citrus growing region as prepared for this pest as is humanly possible.

All of the ag regulatory agencies are extremely active at this point as well. The lessons learned in Florida were put to work early in California. However, make no mistake: The Asian citrus psyllid and the bacterial disease (HLB) that it is capable of carrying and transmitting effectively will put the California citrus industry to the toughest test in its history.

(For more, see: California citrus growers schooling on Florida for coming HLB war)

The importance of staying informed as to quarantine and control measures by attending meetings sponsored by your local county Ag Commissioner’s office, University of California Cooperative Extension Offices and others cannot be overemphasized. I believe we have the right people, energy and spirit of cooperation to successfully neutralize this threat.

HLB is spreading in Mexico, Florida and other parts of the world. I have enough experience in living in the San Joaquin Valley, in interacting with fellow horticulturists, and as a U.C. farm advisor to know that we have individual citrus trees and, probably, collections of citrus trees grafted to materials that entered the country ‘informally’. Limes and pummelos are probably the best examples. Hopefully, none of these trees are a reservoir of HLB just waiting for the Asian citrus psyllid to visit and spread this disease throughout the industry. If such a collection exists and has lost trees to unexplained causes in the past, then an immediate reason for concern is present.

For decades now, propagative budwood should have been obtained only from registered sources. For an example of a clean budwood source see the following website It is absolutely critical now, for the health of your own trees and the citrus industry, not to graft budwood obtained from unknown, untested rees or sources, especially if these sources originated outside of the San Joaquin Valley.

Craig Kallsen, Citrus, Pistachios/Subtropical Horticulture Advisor: or 6618686221, UCCE.