On Friday, August 31st the Woodlake High School 9th grade Agriculture Academy students, led by teacher Don Thornburg, had the opportunity to visit the UC Lindcove Research Center. This visit was the kick off to their 9th grade Project Based Learning (PBL) which will help train them to produce and present an AgriScience project of their own. Dr. Beth Grafton-Cardwell and her team, Stephanie Doria and Narges Mahvelati, provided instruction on using the scientific method and how to apply it as it relates to citricola scale infestations of citrus. Woodlake students became scientists for the day and applied the principals and methods that agricultural researchers use daily.
Thirty Hanford Ag Academy 9th grade students, led by teacher Jason Ferreira came to Lindcove REC to experience Agricultural Science on August 30. Students studied the biology of the citricola scale, collected scale-infested leaves that had been treated with various chemicals, evaluated the survival of the scales, and calculated and graphed the response of the scales to the treatments. This annual event provides the students with a real-life example of how science is conducted in an agricultural setting. Dr. Beth Grafton-Cardwell and her assistants Stephanie Doria and Narges Mahvelati taught the class.
Monserrat Monsevalenzuela organized a visit to California by a group of Chilean researchers, nurserymen and regulators tto speak with various groups about how the California citrus industry is responding to Asian citrus psyllid and huanglongbing disease. At the Lindcove Research and Extension Center, Director Dr. Beth Grafton-Cardwell spoke about the Lindcove REC research program, citrus IPM and the status of the ACP/HLB management program. Casey Schoenleber spoke about the Citrus Clonal Protection Program and Dr. Melinda Klein spoke about the Citrus Research Board research program.
- Author: Irene Lavagi
In 1998, as part of a series of preliminary Citrus Research Board (CRB)-supported trials, navel orange trees treated with a dwarfing agent were planted at the Lindcove Research and Extension Research Center (LREC). The dwarfing agent used in these trials, a small RNA molecule named “Transmissible small nuclear Ribonucleic acid” (TsnRNA”) resulted in a dramatic reduction in tree size. Most importantly for citrus growers, fruit yield per canopy volume and fruit quality (size, color, sugar/acid ratio) of these TsnRNA-treated trees was not affected while double number of trees could be planted in the same land surface (up to 400 trees per acre).
Almost 20 years after planting, the threat of HLB brought about a renewed interest in this potential technology. When growers saw the dramatic reduction in size of these trees during a visit to LREC in November 2014, they expressed a strong desire to explore this technology.
Production of commercial dwarfed trees is key to the successful development of high-density plantings (potentially under protected screens – CUPS), which will be critical to meet future citrus production challenges. To assess the potential savings offered by the employment of this application, UC Riverside scientists are investigating nitrogen fertilizer requirements, nutrient uptake efficiency, water-use efficiency, pesticide application efficiency and savings in labor time for several horticultural operations such as hedging, spraying, fruit harvesting, and tree inspections.
Last winter, fruit nutrient analysis was performed so that fertilization efficiency can be determined. This spring, LREC staff brought several electrical outlets to the field so that equipment to monitor water uptake could be set up. UC Riverside scientists installed sap-flow sensors into the trunks of the dwarfed trees and connected them to dataloggers so that data on water use-efficiency can be calculated.
This CRB-supported project has also fostered the collaboration between the Microbiology and Plant Pathology Department and the Botany and Plant Sciences Department at UC Riverside. Dr. G. Vidalakis, Dr. I. Lavagi, and Dr. R. Christiano work with Dr. L. Santiago and Dr. C. Lovatt to determine the potential of this technology for the California citrus industry.
- Author: Therese Kapaun
- Editor: Beth Grafton-Cardwell
Annual CTV testing of all trees at the Lindcove Research and Extension Center was completed in April. Four hard-working field staff sampled 11,000 trees by blotting the cut ends of four stems per tree onto nitrocellulose membranes. Membranes were bulk processed with DAS-ELISA in the Lindcove Plant Pathology Lab. Samples found to contain the virus were further tested for strain type using RT-qPCR. Trees that were found to be positive will be removed to protect the research program and foundation trees at Lindcove.
Therese Kapaun, LREC Staff Research Associate, used TaqMan probes to determine that samples were infected with the T30 strain, which is the common asymptomatic strain in the Central Valley. Further, she tested all positive samples for presence of MCA13 reactivity, as trees can be co-infected with multiple strains. Fortunately all trees were negative for this epitope, as this is the strain that reveals potentially virulent isolates, which are found in low incidence in this area.