- Author: Therese Kapaun
Dr. William Cheung is a chemist working for the Department of Mechanical and Aerospace Engineering, UC Davis. In this photo he is sampling a navel orange tree at Lindcove REC that is infected with Citrus Tristeza Virus (CTV). He is using a device that utilizes Differential Mobility Spectrometry (DMS) to detect diseased plants that appear healthy. Stressed or diseased plants release unique volatile organic metabolites resulting from host-plant interactions, which can be detected by DMS. The device fits into the small metal case pictured here, and is connected to a laptop PC. Dr. Cheung’s group is currently testing a similar DMS device to detect Huanglongbing (HLB) in Florida citrus. The group hopes to develop a robotic platform that will automatically move the device throughout an orchard, sampling each tree as it moves along.
- Author: Elizabeth E Grafton-Cardwell
In the 1990s, the Citrus Research Board gifted a Sunkist electronic fruit grading system to Lindcove REC, that greatly expanded our postharvest research capabilities. We recently upgraded the citrus fruit grading system at LREC with a Compac line, thanks to another generous gift from the Citrus Research Board. Dan Hostetler, Chair of the Plant Sciences and Technology Department at Cal Poly Pomona, heard that we were replacing the Sunkist line and contacted us to see if we could pass it on to his department. We are pleased to say that the Sunkist grader is on its way down to the Cal Poly Pomona campus where it will be used to train students in techniques of electronic grading and sorting of fruit. A wonderful collaboration between Universities and the citrus industry and a great use of this equipment!
- Author: Elizabeth E Grafton-Cardwell
The photo shows an 8-year-old Tango mandarin tree at Lindcove that is being harvested. Dr. Mikeal Roose (UC Riverside Botany and Plant Sciences) is conducting research in this plot to look at various lines of Tango on differenct roostocks to see how they behave long-term.
- Author: Elizabeth E Grafton-Cardwell
Many of you have heard, that huanglongbing was found in a tree in a yard in Hacienda Heights in southern California. The disease was found by collecting live Asian citrus psyllids at a trap location into alcohol and testing them for the pathogen. When infected psyllids were found for this location, all the trees in that site were tested, and one came up positive for the disease. The tree was a lemon topworked with pummelo and it was the pummelo that was infected. State and Federal officials are doing traceback to find out where the pummelo bud came from. All of the trees in the area are being treated with pesticides, the infected tree has been removed and all nearby trees and psyllids have been tested and were negative for the disease. We are not surprised by this situation, we have expected all along that illegal infected budwood has likely been brought in from Asia and used to create trees and the pathogen is sitting in trees waiting to be picked up by the psyllid. Questions are being asked as to what the grower response should be. The Hacienda Heights infection site is in an urban area, far from commercial citrus. There are only a handful of citrus groves that have had psyllid infestations (Imperial, Ventura and San Bernadino counties) and these have been treated with insecticides. The most important thing that growers and pest control advisors can do is carefully examine their citrus trees for evidence of the psyllid during periods of flush. Insecticide treatments for Asian citrus pysllid should not be initiated until there are actually psyllids in the grove.
The CDFA site http://www.cdfa.ca.gov/plant/pe/interiorexclusion/acp_quarantine.html
shows the ACP and HLB Quarantine maps.
- Author: Elizabeth E Grafton-Cardwell
Lindcove recently hosted a Tulare-Kings Master Gardener citrus training day with farm advisor Michelle LeStrange. The featured speakers were Lance Walheim who spoke about citrus varieties, Neil O'Connell who discussed irrigation and fertilization, Beth Grafton-Cardwell who described common citrus pests and their management, and Georgios Vidalakis who explained how disease-free citrus trees are created and warned about deadly citrus diseases around the world. Craig Kallsen demonstrated citrus tree pruning while the group wandered about the demonstration orchard and tasted fruit. We enjoyed 'training-the-trainers'.