The latest National Agricultural Statistics Service (NASS) results are out for the citrus crop. These are results that are collected by the USDA to gauge production in the different growing areas of the country. From this most recent data, it is clear that citrus production is diminishing with time, most likely the effect of Huanglongbing. This is about a 60% decline from 2015.
The impact of this reduced production has reached out to not just growers, but also the juice industry they support, or are supported by. There's been a decline in the number of juice plants since 2014 which are reliant on volume to stay in business. If plants close, growers have fewer options for their juice citrus. http://www.theledger.com/news/20140705/at-least-one-juice-processor-expected-to-close
Most commercial crop production figures are collected by state and summarized on a state basis with the Agricultural Census every 10 years - https://www.agcensus.usda.gov/. The last was done in 2012.
Daily market prices for these different commodities can be seen on a wholesale basis by city, at USDA's Market News Service - https://www.marketnews.usda.gov/mnp/fv-home . This gives current prices and archived prices for products sold in different markets. It gives a general idea of what the grower will be paid for a given crop.
All of these sources are helpful for deciding where crop prices and markets are going. If you have time check them out.
- Author: Alireza Pourreza
Kearney Research and Extension Center, University of California Cooperative Extension
California is the major producer of fresh market citrus in the U.S., a $2 billion industry that is threatened by a devastating disease called citrus Huanglongbing (HLB). Unfortunately, there is no cure for this disease and if a tree gets infected, it will die in a few years. In Florida, HLB was first seen in 2005, but after a few years the entire state of Florida got infected. Today, about 60% of Florida citrus has gone, mostly because there was no efficient HLB monitoring practice. HLB diagnosis using laboratory-based methods required manual sampling and they were time and effort consuming. An efficient HLB management requires high spatial and temporal resolution monitoring and eradication of infected trees. Therefore, a diagnosis sensor is needed for detecting HLB infected canopies before the development of symptoms. For high resolution monitoring, the sensor should also be able to conduct rapid and inexpensive inspection with high accuracy.
Starch accumulation in HLB infected leaves is an early indication of the disease. Starch has an optical characteristic of rotating the polarization plane of light. We employed this characteristic of starch to develop an early detection methodology in which the sensing system was very sensitive to the rotation in polarization plane of light. The sensor has a customized illumination system including 10 high-power and narrow band LEDs at 591 nm and a polarizing film. The sensor also has a monochrome camera equipped with a linear polarizing filter that is set in a perpendicular direction to the polarizing film of the illumination system.
Starch accumulation in an HLB infected leaf generates blotchy mottle in an asymmetrical yellowing pattern. Deficiency of certain nutrients such as Mg and Zn causes symptoms similar to HLB.
The sensor was mounted on a gator vehicle and was tested in a citrus grove in Florida. The polarized images acquired from healthy, HLB, and Zn deficient canopies were further analyzed for diagnosis purpose.
HLB samples were accurately identified from healthy and Zn deficient samples. Also, the sensor was able to detect HLB within Zn deficient samples.
The polarized imaging methodology was adopted in two separate studies at the University of Florida to investigate the earliest time HLB can be diagnosed by polarized imaging technique after infection. In one study, two-year old Valencia orange plants were inoculated using disk-graft method.
Time-lapse polarized images of leaves from inoculated citrus plants were acquired on a weekly basis. HLB symptoms (as starch accumulation) started to become visible in the polarized images five weeks after inoculation, while the plants were still in asymptomatic stage.
In another study, the polarized imaging methodology was employed to detect HLB in insect inoculated citrus seedlings while in asymptomatic stage. Citrus seedlings were exposed to intensive HLB-positive Asian Citrus Psyllid (ACP) feeding. Polarized images were acquired two times; once after one month after inoculation and again two months after inoculation. As well as HLB detection, the level of infection was obtained for different leaf samples. Polymerase chain reaction (PCR) tests were conducted to validate the HLB status and the level of infection in each leaf sample.
Currently, we focus on improving the accuracy and early detection performance of the polarized imaging sensor and developing a commercialized product for practical in-field diagnosis. This affordable tool can help the California citrus growers to protect their groves from HLB.
Photos, from top to bottom:
Leaf Symptoms of HLB and Zn Deficiency
Time Lapse Images of HLB Infected Leaves Over Time
- Author: Jeanette Warnert
Newly appointed UC Cooperative Extension agricultural engineering advisor Alireza Pourreza has been awarded the 2016 Giuseppe Pellizzi Prize by the Club of Bologna, an honor presented every other year to the best doctoral dissertations focused on agricultural machinery and mechanization. The Club of Bologna is a world taskforce on strategies for the development of agricultural mechanization.
Pourreza, who earned his Ph.D. at the University of Florida in 2014, worked on early detection of Huanglongbing disease of citrus. Huanglongbing, an incurable disease that is spread by Asian citrus psyllid, has seriously impacted citrus production in Florida. The disease has been found in commercial and residential sites in all counties with commercial citrus.
Early detection allows growers to remove infected trees before the disease can spread to healthy trees. Currently HLB infection is confirmed when leaves with yellowing and blotches are submitted for PCR testing, which is expensive and time consuming. However, the yellowing can be also symptomatic of other conditions, such as nutrient deficiency.
“We discovered we could see the symptoms of Huanglongbing using a camera, a set of cross-polarizers and narrow band lighting before it is visible to the human eye,” Pourreza said.
He said the yellow blotches on HLB-infected leaves are caused by starch accumulation.
“If we could detect abnormal levels of starch in the leaf, we could tell it is affected with HLB,” Pourreza said. “Starch showed the ability to rotate the polarization plain of light. We used this optical characteristic to develop the sensing methodology.”
Pourreza said the team has patented the technique and is working on developing a commercial product. He is seeking funding to continue the research in California, where, to date, HLB has only been detected in isolated Los Angeles neighborhoods. Asian citrus psyllid is found in important California commercial citrus production regions from the Mexican border to as far north as Placer County.
Pourreza is based at the UC Kearney Agricultural Research and Extension Center in Parlier.
Entomology Specialist and Lindcove Research and Education Center Director keeps her Asian Citrus Psyllid website for homeowners up-to-date at: http://ucanr.edu/sites/ACP/Homeowner_Options/Homeowner_Resources/
Check it out.
Photo: ACP Adult and Nymphs with wax tubules
What this means is that there is different feeding behavior on different scion varieties that is unaffected by the rootstocks used in this study. This does not mean "a" rootstock can not have an effect, just that the ones used in this trial did not.
EFFECT OF DIFFERENT CITRUS SCION AND ROOTSTOCKS
COMBINATION ON FEEDING OF Diaphorina citri
Alves GA1, Beloti VH1, Carvalho SA2 & Yamamoto PT1
1Escola Superior de Agricultura ‘Luiz de Queiroz'/
Universidade de São Paulo, Piracicaba, SP, Brazil; 2Instituto
Agronômico (IAC), Centro de Citricultura, Cordeirópolis, SP,
Brazil; e-mail: email@example.com
The Asian citrus psyllid (ACP) is the vector of bacteria associated to the huanglongbing and has a host range of more than 50 species of the Rutaceae family. The knowledge about the feeding behavior in different hosts can show useful aspects for future studies of plant resistance and ACP management. Therefore, was evaluated the effect of different combinations of scion and rootstock of citrus in the feeding of ACP adults. For this, we tested Valencia, Pera and Hamlin sweet orange, Ponkan mandarin and Sicilian lemon grafted on Rangpur lime and Sunki mandarin rootstocks.
The flushes were individualized with cages made of transparent plastic cup and “voile” tissue. To collect the honeydew, discs of filter paper were placed at the base of each flush. The adults fed for a period of 72 h. After this, the discs were removed and immersed on the ninhydrin solution. After 24 h, the drops area of honeydew was determined using the Quant software. The feeding was more intense on sweet orange varieties, with a highest value observed to Valencia (0.902 cm2) and the smaller area to Ponkan mandarin(0.269 cm2). Unlike observed for scion varieties, when different rootstocks for the same scion variety were tested, no difference was observed in the consumption of ACP.
Rootstocks can have a tremendous effect, but not in this case with the rootstocks used