June is a busy time of year for potting rootstocks in the LREC greenhouses.  This month we will be transplanting nearly 3000 seedlings to give them time to grow before budding this fall with various scions for four research projects. 

Gerry Perez, Senior Agricultural Technician, is directing the soil sterilization procedure for the potting mix, which we make ourselves.  We use a concrete mixer to combine the soil ingredients, pour the mixture into a custom built steam trailer, and then heat the mixture to 210° F for 30 minutes.  The pots are also heat-treated at this temperature.

 

Last week Lindcove hosted the CCPP annual Foundation Block Walk-Through led by Director Georgios Vidalakis and Robert Krueger of the USDA and attended by growers and nurserymen.  The event featured a display and tasting of more than 70 late season citrus varieties, including navels, mandarins, grapefruits, kumquats, blood oranges, valencias, and specialty varieties.

Following the Walk-Through, the California Citrus Nursery Society held a Variety Committee meeting in the Conference Building.  This event included talks and PowerPoint presentations by Tom Delfino, Richard Lee, Ray Yokomi, Georgios Vidalakis, Claire Federici, Tracy Kahn, and Karen Suslow.

The Citrus Clonal Protection Program (CCPP) is updating it's budwood ordering system, with an improved website coming soon at http://ccpp.ucr.edu/budwood/budwood.php

Screenhouse mother trees at Lindcove are managed by Staff Research Associate Dr. Rock Christiano.  Rock is based here at Lindcove, and orders for budwood can now be filled monthly, in lieu of seasonally as in the past. Information not found on the website regarding the availability of budwood, early release budwood, as well as other questions pertaining to CCPP can be directed to Rock at christiano@ucdavis.edu

The next budwood cut is scheduled for June 13, then monthly thereafter.  Check the CCPP website for future cutting dates.

A late-season fruit tasting and CCPP Foundation Block walk through for citrus growers and nurserymen is scheduled for May 30 at Lindcove from 9:00 -11:30.  

Annual disease testing for Citrus tristeza virus (CTV)  is nearly complete at LREC.  Each year we test all field trees for presence of the virus using the Direct Tissue Blot Immunoassay method, which is a form of ELISA.  This year we have more than 11,000 trees to test.  CTV is found in the phloem tissues of citrus plants, and virus titer is typically highest during April in the San Joaquin Valley. 

Field technicians Cody McCarter and Jessica Seymore work as a team to collect the tissue, which can be in the form of young flushing stalks or leaf petioles.  The stalks or leaves are taken from the tree and the ends snipped with a cigar cutter for a smooth cut that is pressed onto a nitrocellulose membrane.  The leaf material is then discarded, as the blots made onto the membrane contain enough phloem to reveal presence of the virus.  Membranes are processed in-house in a laboratory, and results are obtained within four hours.  Trees that are found to be infected are removed in order to protect research plots and foundation trees from infection.