- Author: Ben Faber
This is the abstract of a presentation that was made at the recent Huanglongbing Conference held in Orlando, FL. This and other paper abstracts will soon be available at: http://irchlb.org/files/33373ab0-7df3-4117-9.pdf
Spray application of different kaolin formulations on sweet orange plants disrupt the settling and probing behavior of Diaphorina citri
M. Miranda1, O. Zanardi1; H. Volpe1; R. Garcia1; N. Roda2, E. Prado3
1 Fundecitrus, Araraquara, Brazil, 2 Tessenderlo Kerley, Inc./NovaSource, Phoenix, USA, 3 Universidade Federal de Lavras, Lavras, Brazil.
Abstract: The psyllid Diaphorina citri is the vector of the bacteria associated with huanglongbing (HLB), which is the most destructive citrus disease worldwide. Chemical control is the primary tactic against this insect. However, alternative methods are important to achieve a more effective control in an integrated pest management programs. Thus, this research was carried out to assess the influence of different kaolin formulations on the settling and probing behavior of D. citri. In both studies, two wettable powder (WP) kaolin formulations (Tessenderlo Kerley, Inc./NovaSource) were sprayed three times at different concentrations on sweet orange plants. In the experiment to assess the settling behavior, three concentrations (3, 5 and 7% w/v) of both formulations were tested. A non-choice test was performed, where 16 adult psyllids were released in a cage with seedlings of the same treatment, and the number of psyllids/plant at different time intervals was counted. For the probing trial, the electrical penetration graph (EPG) technique was used. Adult psyllids were monitored for 6 h on nursery citrus trees treated with two kaolin formulations at 3 and 5% w/v. The two kaolin formulations have a repellent effect on D. citri, causing an overall reduction of 40% of psyllids settled on treated seedlings compared with untreated control. Moreover, both formulations disrupt D. citri probing behavior, with a significant reduction (60%) in the proportion of psyllids that reach the phloem compared with untreated nursery citrus trees. In general, there were no differences between the kaolin formulations and among the concentrations tested in both experiments (settling and probing). Then, both formulations could be used in an integrated D. citri management program. These findings reinforce the recommendation of kaolin application on young citrus planting as a useful strategy for HLB management, mainly on the edge of the farms.
Photo: ACP Feeding
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- Author: Ben Faber
The recent Huanglongbing Conference in Orlando, FL was chock full of people and ideas. Some of the ideas were still in the fermentation state and some were in practice on farm. One of the ideas that has been put into practice is the use of antibiotics, such as tetracycline and streptomycin to control the bacteria, Candidatus Liberibacter asiaticus (CLas), which causes HLB or citrus greening. This is somewhat disturbing since the rise of antibiotic resistant bacteria which affects humans has been affected by the wide-spread use in animal production facilities. This has led to some food companies to discontinue the sourcing of meat from animals treated with antibiotics for non-health reasons.
Antibiotics are molecules that limit the growth or reproduction of bacteria. They come under the umbrella of bactericides which include antibiotics, but also disinfectants like bleach and copper sulfate and antiseptics like peroxide, iodine and alcohol. Antibiotics when properly used will not harm human tissue and can be derived from bacteria, fungi and synthetically and will often act directly on the bacteria that is causing the disease. Some of these molecules can be simple assemblages of amino acids called peptides (etymology “to digest”) or strings of peptides called proteins. And sometimes they do not work on the bacteria itself, but on steps that lead up to processes that make the bacteria effective at its job.
At the conference, several papers were presented that illustrated this type of antibiotic effect. One of these papers was presented by Robert Shatters for his group. The peptide they are looking at actually inhibits the movement of the CLas bacteria in the gut of the insect, reducing or possibly preventing the transmission of the bacteria to the host plant – citrus.
The following is an abstract from the paper.
Identification of gut epithelium binding peptides that reduce systemic movement of ‘Candidatus' Liberibacter asiaticus within the Asian citrus psyllid vector
Robert G. Shatters, Jr1, Dov Borovsky1, El-Desouky Ammar1, David Hall1, Kasie Sturgeon2, EricaRose Warwick2, Marc Giulianotti3, Radleigh G Santos3 and Clemencia Pinilla4
1USDA, ARS, USHRL, Fort Pierce, FL USA; 2University of Florida, CREC, Lake Alfred, FL USA; 3Torrey Pines Institute for Molecular Studies, Port St Lucie, FL USA; Torrey Pines Institute for Molecular Studies, San Diego, CA USA.
Non-Technical summary: The Asian citrus psyllid is the only known vector of the bacteriumthat causes citrus greening disease. This insect acquires CLas from an infected citrus tree while feeding as a nymph. Transmission to uninfected trees occurs when infected adults emerge and fly off and feed on uninfected trees. Our current understanding of the CLas-psyllid interaction suggests that adults become competent for transmission only after the bacterium moves from the insect gut into the hemolymph and then to the salivary glands. We have identified a set of small peptides that when fed to the psyllid, bind the gut membranes and reduce the ability of the citrus greening bacterium to move from the gut to the salivary glands. These peptides are now being tested to determine if they can be used as an effective way of reducing the spread of citrus greening disease.
This and other paper abstracts will soon be available at: http://irchlb.org/files/33373ab0-7df3-4117-9.pdf
photo: HLB Symptoms
- Author: Ben Faber
A new ruling from CDFA to modify the announcement from March 2. Read on:
CDFA suspends enforcement of new citrus rule |
The California Department of Food and Agriculture announced March 2 that it was suspending enforcement of a new regulation regarding transport of bulk citrus, the day after the new rule took effect. The department said "the decision was made as a courtesy to the citrus industry to allow for additional time to prepare citrus operations to comply with the new rule, which requires all bulk citrus loads to be fully covered regardless of the origin or the destination. Additionally, CDFA is continuing to process and return compliance agreements." Although enforcement has been suspended indefinitely, CDFA is expecting haulers to voluntarily abide by the new rule. Compliance can be achieved several ways, including but not limited to the use of a shipping container, tarp, enclosed vehicle (including curtain vans), or another method that completely covers bulk citrus during transport. If using a tarp, tarps must reach the bed of the truck. |
From March 2, 2017
From AgNet West, http://agnetwest.com/2017/02/27/citrus-tarping-starts-march-1/
As of March 1, 2017, all citrus loads traveling throughout the state of California have to be tarped. This regulation aims to reduce the accidental transportation of the Asian citrus psyllid (ACP).
The Citrus Pest and Disease Prevention Program (CPDPP) is helping to get the word out about the new regulation. “That regulation is stating that every load, regardless of origin or destination, must be tarped,” CPDPP Grower Liaison Erin Betts said. “You don't have to use a tarp. You can use a van or something that is completely covered on all four sides, down to the bed.”
Counties north of the grapevine region have been noticing a trend with ACP finds in the area, and the new tarping regulation hopes to limit some of the accidental transportation the industry is seeing. “When we started having finds, they were all along the major transportation corridors,” Betts said. “So if we cover these loads that are coming and going from wherever, we are preventing that psyllid from hopping off … at a stop light or a stop sign in the middle of the Citrus Belt, Kern County or anywhere.”
All citrus loads being transported in California will now have to be fully covered by tarps. The state passed an emergency law that makes tarping mandatory in an attempt to reduce the accidental spread of the Asian citrus psyllid (ACP).
From the Citrus Pest and Disease Prevention Program (CPDPP):
The California Office of Administrative Law approved an emergency rule that requires all bulk citrus loads to be fully tarped during transport regardless of where the load originates from or its destination. The statewide mandatory tarping regulation is in response to a recommendation from the Citrus Pest and Disease Prevention Committee (CPDPC) to prevent the spread of the Asian citrus psyllid. The California Department of Food and Agriculture will begin contacting growers, haulers and packers to re-sign compliance agreements that include the tarping requirement. These entities are urged to begin preparations now while they wait to receive new compliance agreements.
Why did the Citrus Pest & Disease Prevention Committee ask for a mandatory tarping regulation?
The statewide mandatory tarping regulation is a preventive action to address the spread of the Asian citrus psyllid, and is in response to an analysis conducted by the University of California that looked at Asian citrus psyllid find patterns along transportation corridors. As the number of psyllid finds increase in commercial citrus regions and along major transportation corridors, the CPDPC felt the action was a necessary step to help prevent the spread of Huanglongbing – the deadly citrus tree disease that the psyllid can carry.
What are the regulatory requirements?
The new requirement is a statewide regulation that restricts the movement of regulated articles from “or within” a quarantine area. Revised compliance agreement exhibits will require all bulk citrus loads to be fully tarped regardless of where the load originates from or its destination, even loads that are traveling within a county. Specifics of the requirements will be released soon. In the meantime, producers can review USDA's tarping compliance requirements for general guidelines. Read the full press release from the CPDPP.
New tarping rules are in effect for California citrus. The industry must comply, or it will face costly penalties. Tarping fines could add up to $10,000.
A new regulation requires citrus loads to be tarped or fully enclosed as they travel through the state. “There were new compliance agreements that were mailed out,” Citrus Pest and Disease Prevention Program Grower Liaison Erin Betts said. “The new regulation states that every load, regardless of origin or destination, must be tarped.”
Betts said not complying with the new rules can be very costly. “The fine is not only for if you don't have your load tarped properly, but also if you do not have your compliance agreement with you,” Betts said. “That violation could be up to $10,000.”
According to Betts, the industry has many ways to make sure they are properly complying with the regulation. “(The industry) can contact the county, local grower liaisons and also the California Department of Food and Agriculture.”
- Author: Ben Faber
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: Ben Faber
This has been a hot time. Look for irrigation problems, but also look for other weather related problems. This is possibly the most shocking.
If you see your citrus tree suddenly collapse. It happens on a weekend or in a few days, and it has suddenly turned hot with a Santa Ana or Sundowner, it is quite likely "Dry Root Rot". This is a situation where the water conducting tissues, the xylem, have been clogged by fungi and when a sudden demand for water comes from the weather, the tree collapses because it can not support the movement of enough water to satisfy that demand. It is more common along the coast than the Valleyk, but it does occur there, as well.
It starts with some type of wound to the crown roots or stem - gophers or field mice nibbling away at the roots or crown. Or damage from weed whipping or some sort of mechanical damage. This allows entry of the Fusarium fungus that causes the xylem clogging. You can usually see the damaged tissue just below the bark, near the base of the tree. The damage has usually occurred several years prior and takes awhile for the fungus to do its clogging. There's no know cure for this situation. Cut the tree out. It's not particularly contagious as far as we know. The fungus is cosmopolitan, meaning it is found in most orchards, and it just waiting for a wound to invade. You can replant into the orchard, but just avoid causing wounding.
Dry root rot affects all citrus species and varieties.
http://ipm.ucanr.edu/PMG/r107100211.html
Photos:
Collapsed canopy, grapefruit
Dead tissue below the bark