Jose Jimenez and Brian Fien, CAPCA Citrus & Sub-Tropical Crop Team PRUNING IS A CULTURAL practice which varies greatly in philosophy and practice among citrus growers in the San Joaquin Valley. The cost of pruning is one of the most important factors for many growers. Within most farming operations, owners, farm managers, and supervisors have the most control over pruning activities. Applicators and PCAs perform chemical applications. They are the ones who select materials, rates, and conduct applications. It’s very important that applications, recommendations, and operations are processed cohesively to optimize California red scale (CRS) control. Applicators should work with growers and PCAs to determine how pesticide applications will work best in relation to the coverage and canopy structure of the orchard. With the drought experience of the last few years, strong 4th and 5th flight populations have been able to successfully overwinter inside citrus trees especially, highly dense citrus orchards that don’t receive much pruning. Highly dense orchards will have a much harder time receiving good or excellent control of CRS. And in every scenario, it can be a challenge.
APPLICATOR ALERTS IN THIS
ISSUE:
We’re not going to state what the exact program must be, but the following factors should be considered to determine what the potential pruning program could be. Very important factors would be: the tree longevity, commodity, profits, past results of spray program, and the gallons per acre. Is the orchard on the brink of being pushed because of aged lost productivity? Does the commodity have the value in justifying increase control cost? Has the spray program for scale pests been truly successful? How many times in the last few years have you had to come back and spray the same orchard? If you continue or already use high gallon per acre tank mixes, is your cost increasing but you’re not seeing the control you expect? Has rotating chemistries been consistent enough to see that nothing really seems to get good control? These questions may help to determine what the appropriate pruning program can be. Growers should add up the labor, increased fixed cost, and pesticide cost. Then see if there is room to try more pruning on a few trees, acres, or orchards. The bottom line is that dense trees make it easier for scale pests to hide from pesticide applications. They can move around the tree and orchard much easier and provide a cool shaded habitat for their optimal survival. Also, birds and rodents would rather harbor themselves in cool shaded trees. They also carry scale pests tree to tree. In our experience, systemic pesticides will work best if the inner canopy is clean of suckers, crossed limbs, crows-feet, and inter-tangled limbs. And a plus, soft scales such as cottony cushion scale and citricola scale will also be easier to control by maintaining the tree from becoming too dense inside. Pruning will vary from variety and commodity. Suckering two or three times in the summer helps keep down the crossed limbs that begin to densify the orchard. There’s also the benefit of higher quality fruit. Fruit that doesn’t rub against dense limbs has better appeal and less blemishes. Taking a good look at trees within the orchard will help determine what steps need to be taken. Communication, between ownership, farm management, PCAs and applicators, is definitely going to help with the fight against California red scale populations and other know pests.
MARCH 2017 VOL. 1I, NO. 1
Lower gallons per acre tank mixes such as 100, 125, or no more than 250 gallons per acre, combined with systemic control pesticides, seem to hold back scale from getting on fruit or outer leaves most of the time. But the true inner populations that overwinter can survive through these applications, and will often come back, with a strong retreat population - especially if the inner limbs, which many times end up drying up and semi dying back, host mature female red scale populations. Foliar systemic pesticides will be much harder to get into the inner wood canopy of the tree. And the continued use of foliar systemic pesticides without rotation will reduce control of the outer ✔ Prunin g in Citru canopy of the s - p. 1 ✔ CAPC tree. Because A ED Ca lendar the inner p .3 ✔ ACP/H LB Contr population ol - p. 4 ✔ Citrus will continue Matters - p. 5 to slowly ✔ Shoot & Twig D move inside ieback - p .6 out and get ✔ UC R esources - p. 7 stronger every ✔ Boots generation, on the G round - p . 8 ✔ HLB F orecastin g in CA p. 10
biological control, such as the release of Aphytis, can successfully aid in CRS control. But beneficial survival has been tough the last few dry, dusty, drought years. Contact pesticides work great with proper rotation, oils, and or sticker spreaders, in controlling red scale. But again, growers push for more control, therefore PCAs become more product selective, and applicators find themselves going higher gallons per acre every year. They should take a look at their pruning program, especially when considering going higher gallons per acre.
APPLICATOR ALERTS
Pruning in Citrus
CAPCA ED – 2017 Schedule Mark your calendars now for these valuable training events. March 21, 2017 – Redlands – CAPCA ED March 23, 2017 – Modesto – CAPCA ED March 23, 2017 – San Luis Obispo – CAPCA ED March 29, 2017 – Exeter – CCA Nutrient Management April 11, 2017 – Escondido – OFAC April 26, 2017 – Carson – CAPCA ED April 27, 2017 – Simi Valley – CAPCA ED May 3, 2017 – San Jose – CAPCA ED May 23-24, 2017 – Temecula – CAPCA Spring Summit June 13, 2017 – Palm Desert – CAPCA ED June 22, 2017 – Sacramento – CAPCA ED June 28, 2017 – Oxnard – OFAC July 11, 2017 – Lodi – CCA Nutrient Management July 26, 2017 – Fresno – Nutrient Management August 2, 2017 – San Mateo – CAPCA ED August 2, 2017 – Ontario – CAPCA ED August 10, 2017 – Tulare – OFAC August 15, 2017 – Carlsbad – CAPCA ED August 17, 2017 – Simi Valley – CAPCA ED August 24, 2017 – San Luis Obispo – CAPCA ED September 12, 2017 – San Jose – CAPCA ED September 13, 2017 – Santa Paula – CAPCA ED September 14, 2017 – Bakersfield – CAPCA ED September 21, 2017 – Modesto – CAPCA ED September 27, 2017 – Chico – CAPCA ED October 15- 17, 2017 – Reno, NV – CAPCA Conference Watch our website for registration information: https://capcaed.com/ For additional information contact: Ariana Zamora, So. CA CAPCA ED Coordinator ariana@capca.com / (805) 704-3255 Jackie Tabarez, No. CA CAPCA ED Coordinator jackie@capca.com / (916) 928-1625 x205
CAPCA EDITORIAL STAFF
Ruthann Anderson - Editor
Joyce Basan - Deputy Editor Dee Strowbridge - Membership/Conference Sylvia Stark - Advertising Sales Manager Lien Banh - Office Manager Ariana Zamora - So. CA Representative Jacqueline Tabarez - No. CA Representative Rachel Taft - Executive Assistant Graphic Design - Rosemary N. Southward southwardr@comcast.net PURPOSE California Association of Pest Control Advisers (CAPCA) is a non-profit voluntary mutual benefit association. CAPCA’s purpose is to serve as the leader in the evolution of the pest management industry through the communication of reliable information. CAPCA is dedicated to the professional development and enhancement of our members’ education and stewardship which includes legislative, regulatory, continuing education and public outreach activities. PUBLISHING INFORMATION Applicator Alerts is published by the California Association of Pest Control Advisers (CAPCA), 2300 River Plaza Dr., Suite 120, Sacramento, California 95833. Web: www.capca.com, (916) 928‑1625. POSTMASTER: send address change to CAPCA. CAPCA has endeavored to include appropriate and accurate statements, but disclaims any and all warranties and/or responsibility for the statements or articles submitted to Applicator Alerts that may have additionally been edited for style, content and space prior to publication. Views expressed are those of the authors and do not necessarily represent CAPCA policies, or positions or endorsements. Editorial content of this publication is educational and informational in nature. No part of this publication, including images, may be reproduced without prior written permission from the publisher. Contact CAPCA at (916) 928‑1625 for reprint authorization. PRINTING: Sundance Press Tucson, Arizona
FIND US ON LINKEDIN: https://www.linkedin.com/company/californiaassociation-of-pest-control-advisers-capca-
CITRUS ISSUES
Applicators Play a Critical Role in Controlling Spread of the Asian Citrus Psyllid and Huanglongbing Victoria Hornbaker, Branch Chief, Integrated Pest Control CDFA A DEADLY TREE DISEASE called Huanglongbing is threatening California citrus trees that have been growing in backyards and in commercial groves for generations. Spread by the Asian citrus psyllid, a tiny pest that feeds on the leaves and stems of citrus trees, the disease has no cure, and infected trees will die. To help combat the pest and disease, applicators and growers are asked to comply with all county, state and federal regulations, including important Asian citrus psyllid and Huanglongbing (HLB) quarantines. Asian citrus psyllid quarantines have been established for more than 62,000 square miles throughout California that prohibit the movement of citrus and curry leaf plant material out of a quarantine area. For those working with backyard citrus, this means you cannot transport or send citrus fruit or leaves, potted citrus trees, or curry leaves from a quarantine area. For commercial fruit, beginning March 1, 2017, all citrus fruit in bulk containers or bins must be fully covered regardless of point of origin or destination, including within a quarantine area. Additionally, any citrus being moved out of a quarantine area needs be cleaned of leaves and stems prior to movement. Currently, county-wide Asian citrus psyllid quarantines are in place in Fresno, Imperial, Los Angeles, Orange, Riverside, San Bernardino, San Diego, Santa Barbara, Tulare and Ventura. Portions of counties across the state are also under quarantine with the most recent quarantines established within Yolo, Solano and Alameda counties due to new Asian citrus psyllid finds.
review at CDFA and, if enacted, would replace the current Asian citrus psyllid quarantines in place throughout California to restrict intrastate movement of nursery stock, citrus plant material and green waste. A regional quarantine structure will better mitigate intrastate movement of citrus from high-risk to low-risk areas.
• Inspect trees often, especially when there is new flush. Report any suspected findings of the Asian citrus psyllid or HLB disease symptoms to your local agricultural commissioner. • If working in commercial groves, participate in coordinated treatment efforts to reduce populations of the psyllid.
HLB was first discovered in California in 2012 in the Los Angeles County region of Hacienda Heights, resulting in the establishment of an HLB quarantine. Since then more than 37 additional trees have been identified as positive for HLB in San Gabriel and nearby areas. All HLB-infected trees have been residential and have been removed by CDFA. A 275-square mile region is currently under an HLB quarantine, restricting any movement of citrus plant materials out of the area (243 square miles in Los Angeles County and 32 square miles in Orange County).
Visit CitrusInsider.org to view photos of the pest and disease, learn about treatment options and stay informed on the issue and regulatory changes and implications to your business. By working together, we can save California Citrus. Article submitted by the Citrus Pest & Disease Prevention Program, a growerfunded program established to combat pests and diseases that could threaten our state’s citrus industry. Currently, the Asian citrus psyllid and Huanglongbing are the program’s primary focus, with its key responsibilities including detection, urban treatment and educational outreach to commercial growers and residents.
Applicators and growers should stay diligent when working with citrus by following the best practices below: • Be careful not to transfer citrus plant material from one work site to another. Mendocino
Lake
Colusa
Sutter
Placer
Yuba
El Dorado
Yolo
Sonoma
Napa Marin
Sacramento
Contra Costa
Calaveras San Joaquin
Alameda
2017 Asian Citrus Psyllid (ACP) Quarantine Boundaries
Alpine
Amador
Solano
Tuolumne Mono
Mariposa
Stanislaus
Merced
Santa Clara
Madera
Fresno
San Benito
Kings
Monterey
Tulare
San Luis Obispo
Santa Barbara
Be aware that a new regional quarantine structure is under 4
• Inspect all equipment and personal items, and remove all citrus leaves and stems before leaving a site.
Inyo
Kern San Bernardino Ventura
Los Angeles
Orange
Quarantine Boundary Approved: 2/13/2017 62,291 Sq. Miles Map Updated 2/14/2017 MapInfo 15.2.4 StreetPro v 2015.12
Riverside
San Diego
Imperial
COMMERCIAL GROWERS: Protect Your Groves from Huanglongbing (HLB) How to keep your trees healthy and productive for the long term. Take action to combat Asian citrus psyllid and HLB. » Start with preventive pest control. » Follow up with sequential pest treatments, as necessary, to eliminate Asian citrus psyllid populations.
The Asian citrus psyllid is continuing to spread through California and can easily spread between groves. Without monitoring, trees neighboring commercial groves could easily become hosts, bringing the pests and HLB into an otherwise healthy area. Help protect your grove and consider the Abandoned Citrus Tree (ACT) removal program, if necessary. The program is managed by California Citrus Mutual and allows growers to report abandoned trees that could threaten their groves.
» Educate your friends, family and neighbors about Asian citrus psyllid and Huanglongbing identification. » Be sure to report any abandoned trees that could threaten your groves.
Act Now Submit your information by visiting CitrusMatters.us. Once submitted, California Citrus Mutual will work with officials to review and discuss tree removal.
CitrusMatters.us
#CitrusMatters
© 2017 Bayer CropScience LP, 2 TW Alexander Drive, Research Triangle Park, NC 27709. Always read and follow label instructions. Bayer and the Bayer Cross are registered trademarks of Bayer. For product information, call toll-free 1-866-99-BAYER (1-866-992-2937) or visit our website at www.CropScience.Bayer.us.
CITRUS ISSUES
Investigating the Cause of Shoot and Twig Dieback of Clementine, Mandarin and Navel Orange in California Joey S. Mayorquin1, Mohamed T. Nouri2, Florent P. Trouillas2, Greg Douhan3 and Akif Eskalen1
Department of Plant Pathology and Microbiology, University of California, Riverside, CA; 2 Department of Plant Pathology, University of California, Davis, Kearney Agricultural Research and Extension Center, Parlier, CA; 3UCCE Farm Advisor, Tulare County.
1
(Fig.3). These symptoms were primarily reported from clementine, mandarin, and navel orange varieties. In order to determine the main cause of this disease, field surveys were conducted in several orchards throughout the Central Valley. Isolations from symptomatic plant samples frequently yielded Colletotrichum species.
Fig. 1: Shoot dieback symptoms on Clementine (A.Eskalen)
RECENTLY, AN OUTBREAK of shoot and twig dieback disease of citrus has been occurring in the main citrus growing regions of the Central Valley of California (Fig 1). The causal agents of this disease were identified as species of Colletotrichum, which are well-known pathogens of citrus and other crops causing anthracnose diseases. At this time, it is unclear how wide-spread the disease is in California citrus orchards, but surveys are being conducted to evaluate the spread of this disease in orchards.
Field observations indicate that symptoms initially appear during the early summer months and continue to express until the early fall. Trees showing dieback and gumming symptoms characteristic of this disease are usually sporadic within an orchard and generally only a few twigs or shoots are affected within a tree. Morphological and molecular phylogenetic studies allowed the identification of two distinct species of Colletotrichum (Colletotrichum karstii and Colletotrichum gloeosporioides) associated with twig and shoot dieback. Interestingly, these Colletotrichum species were also isolated from cankers in larger branches. Although C. gloeosporioides is known to cause anthracnose on citrus, a post-harvest disease causing fruit decay, it has not been
reported to cause shoot dieback of citrus. C. karstii however has not been reported previously from citrus in California and our laboratory is currently conducting field and green house studies to determine the pathogenicity of this species in citrus. At present, it is unclear how widespread this disease is in California orchards or how many citrus varieties are susceptible to this disease. Applicators are advised to remain alert and monitor citrus trees for the presence of the disease in the Central Valley (particularly clementine, mandarin, and navel varieties) during the early summer months. Continuing research lead by Dr. Akif Eskalen (UC Riverside) in collaboration with Dr. Florent Trouillas (Kearney Agricultural Research and Extension Center), Dr. Greg Douhan (UCCE Farm Advisor Tulare County), and Craig Kallsen (UCCE Farm Advisor in Kern County) is focused on further understanding the biology of the fungal pathogens as well as factors influencing disease expression in order to develop management strategies against this emerging disease.
The disease was first noticed in 2012 by several growers and nurserymen in various orchards in the Central Valley. Symptoms included leaf chlorosis, crown thinning, gumming on twigs and shoots dieback, and in severe cases, branch dieback of trees (Fig.2). The most characteristic symptoms of this disease are the gum pockets which appear on young shoots either alone or in clusters and the dieback of twigs and shoots 6
Fig. 2: Branch Dieback symptoms on Clementine (A.Eskalen)
Fig. 3: Gumming symptoms on Clementine shoot (A.Eskalen)
UC ACP Distribution and Management - http://ucanr.edu/sites/ACP/ UC IPM - How to Manage Pests: Citrus - http://ipm.ucanr.edu/PMG/selectnewpest.citrus.html Degree Days: California Red Scale - http://ipm.ucanr.edu/calludt.cgi/DDMODEL?MODEL=CRS Degree Days: Fuller Rose Beetle - http://ipm.ucanr.edu/calludt.cgi/DDMODEL?MODEL=FRB UC IPM – How to Manage Pests: Avocados - http://ipm.ucanr.edu/PMG/selectnewpest.avocado.html Agriculture IPM Decision Support Tool - http://www2.ipm.ucanr.edu/decisionsupport/ Integrated Pest Management for Citrus Manual - http://anrcatalog.ucanr.edu/Details.aspx?itemNo=3303 Integrated Pest Management for Avocados Manual - http://anrcatalog.ucanr.edu/Details.aspx?itemNo=3503 Mitigating Pesticide Hazards - http://ipm.ucanr.edu/mitigation/index.html UC IPM - Exotic and Invasive Pests - http://ipm.ucanr.edu/EXOTIC/index.html UC Riverside Center for Invasive Species - http://cisr.ucr.edu/ UC Riverside Subtropics Newsletter - http://ceriverside.ucanr.edu/Custom_Program/Topics_in_Subtropics/ KAC Citrus Entomology Web Page - http://ucanr.edu/sites/KACCitrusEntomology/ UC IPM Video Library - http://ipm.ucanr.edu/IPMPROJECT/videolibrary-ag.html UC IPM Online Training Resources - http://ipm.ucanr.edu/training/
STOP RODENT INTRUSION & IMPROVE FOOD SAFETY WITH ®
Paraffinized Chlorophacinone Pellets
For control of Norway Rats, Roof Rats, House Mice & Voles in outdoor, non-crop areas. • Comprehensive Use Label – • includes field border areas adjacent to crops • bait station use • broadcast (for vole control) beyond 100 feet from buildings or structures. • Moisture-Resistant – paraffinized pellet holds up to rain and irrigated conditions.
LEARN MORE
• Superior Attraction & Control with a readily-available antidote: Vitamin K1 Not for use in-crop. Federally Restricted-Use Pesticide; Not a California Restricted Material.
Borderline Baiting protects crops
CITRUS ISSUES
University of California Resources for Citrus/Subtropicals
CITRUS ISSUES
Boots on the Ground: Q & A with Brian Fien PCA & CAPCA Citrus-Subtropical Crop Team Champion, Parlier, CA APPLICATOR ALERTS (AA): Asian Citrus Pysillid/Huanglongbing (ACP/ HLB) is currently the hot topic in the Citrus industry. When ACP/HLB questions come up, what is the first question you hear people ask the most? Brian Fien (BF): [People] are most often inquiring or interested in research and experiences of those affected individuals. Considering most other citrus growing regions have been combating both ACP and HLB for years, there is a plethora of scientific research, but more importantly, [they] want to learn from the failures and success of other citrus growing regions of the world and Florida. California Citrus industry has been inundated with presentations of failures and what not to do as a result of Florida, but there has been some novel discoveries from Florida too. For example, varieties such as the “Bingo” have showed evidence of tolerance to the bacterium. I believe both the failures and successes discovered are key to the survival of California Citrus Industry. (AA): In California, both State and industry officials have been working to stem the insect’s spread. What is important for applicators and growers to do to aid in these efforts? (BF): Continued education of PCAs, growers, and applicators is key in the prevention of the spread of ACP. The insect can be managed with chemical tools currently available to the industry. Growers, PCAs, and applicators are the stewards of the industry. So when County and State officials or ACP regional liaisons’ contact us about finds within a given area, it becomes our responsibility to work with these individuals to strategize and cooperate where asked. What is equally important is the education of pickers, harvesters, truck drivers to be vigilant of moving the pest from one location to another. In order to be successful, it will take an industry wide approach. Any gaps could result in an unintentional spread of ACP or even worse the spread of HLB. (AA): How can the PCA, the applicator and the grower work together in order to identify a possible infestation early? (BF): PCAs, growers, and field scouts need to be vigilant while scouting fields. While conducting other pest scouting functions it is easy to evaluate leaf surface areas in the tree for symptomology of ACP presence. Applicators and growers can contribute by informing irrigators, agronomists, tractor drivers, and pickers how to be vigilant. I believe the more individuals evaluating, the better. (AA): What do you think the outlook is for the citrus industry in the next 3-5 years? (BF): I am trying to be cautiously optimistic as it relates to ACP and more importantly HLB. As a grower myself with a vested interest in citrus, I have witnessed both internal and external industry failures, but at the same time have witnessed success too. As mentioned before, the key for the industry is team work and area wide management approaches. One’s greed or refusal to comply could be detrimental to all others in the industry. However, I am confident growers and agriculture will persevere.
8
(AA): How does CAPCA’s Citrus & Subtropical Team plan to develop their role with the industry? (BF): The Citrus crop team plans to continue to develop and provide PCAs with a platform for daily interaction and resources where applicable. The team also recognizes the opportunity to address critical industry topics, discover and share best practices, and work with industry audience to better and advance the California Citrus Industry. Our teams will be working to help others understand the PCA’s role, training, professionalism, and perspective, and formulate appropriate strategic action between PCAs and other segments of the industry, all while advancing the CAPCA platform. Working from within CAPCA, the teams will develop communication, outreach, and mentoring within the industry.
NEW
CAPCA’S CROP TEAMS
Having trouble monitoring Oriental Fruit Moths in your mating disrupted orchards?
Opt-In to CAPCA’s Crop Teams
www.capca.com
The core concept for CAPCA’s Crop Teams is to be available to all stakeholders and to provide a cadre of experts within the crop team classification who are involved, knowledgeable and interact daily about the specific crop. Our teams recognize the value of branding, reaching members and having momentum of advocacy to outreach to the Boots on the Ground. Teams will provide relevant communication channels for chapters and industry partners regarding risk management on geographic and crop-specific issues. To get more information about CAPCA’s Crop Teams, or to sign up to receive Crop Team information, please visit the web link above or contact Joyce Basan: joyce@capca.com (916) 928-1625 x201
“For use in mating disrupted orchards.” • PHEROCON OFM COMBO DUAL captures Oriental Fruit Moth when OFM pheromone alone is shut down. • Best product to use in your mating disrupted “Stone Fruit” orchards and in “Pome Fruit” when Oriental Fruit Moth is an invasive species.
+
• Captures both male and female Oriental Fruit Moth (vs) males only with OFM pheromone alone.
Contact your local supplier and order now. Visit our website: www.trece.com or call 1-866-785-1313. ®
INCORPORATED INSECT PHEROMONE & KAIROMONE SYSTEMS
Your Edge – And Ours – Is Knowledge. © 2017, Trécé Inc., Adair, OK USA • TRECE, PHEROCON and CIDETRAK are registered trademarks of Trece, Inc., Adair, OK USA
TRE-1051
CITRUS ISSUES
A Practical Solution to Address the Emergence of Citrus Greening Forecasting in California Alireza Pourreza, Assistant CE Advisor, Kearney Agricultural Research & Extension Center and Affiliated IPM Advisor, UC Statewide IPM Program 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 greening or Huanglongbing (HLB). HLB is a bacterial disease, psyllid vectored, and is known as the most dangerous citrus disease. Unfortunately, there is no cure for this disease and if a tree gets infected, it will die in a few years. All commercial varieties of citrus are susceptible to HLB. In Florida, HLB was first seen in 2005, but it spread rapidly across the state after a few years. Today, about 60% of Florida citrus has been destroyed, mostly due to a lack of an efficient HLB monitoring system. Just as one HLBaffected tree in Florida caused a statewide disease spread within a few years, one undetected HLB-affected tree in California can cause the same disaster. In the current monitoring practice, California Department of Food and Agriculture (CDFA) personnel or other agents are conducting inspections and samplings in commercial groves and residential areas. However, human based inspection is subjective and can be affected by external factors. Additionally, HLB diagnosis using laboratorybased methods are expensive and time/effort consuming. An efficient HLB management needs a high spatial and temporal resolution monitoring followed by eradication of infected trees. Therefore, a diagnosis sensor is needed to improve and facilitate HLB detection, especially before the development of symptoms. For high resolution monitoring, the sensor should also be able to conduct rapid and inexpensive inspection with high accuracy. The Asian citrus psyllid (ACP: the vector carrying the HLB bacterium) is widespread in southern California and now is distributing in the Central Valley. Since the first HLB-affected tree was identified in the Los Angeles area in 2012, many other infected trees have been seen in the neighboring area. The HLB threat in California needs to be addressed immediately and HLB must be properly managed before it becomes as pervasive as in Florida. In an optimized HLB management, the disease monitoring scope should be expanded so that more citrus trees could be monitored. Also disease monitoring should be repeated in short-time intervals to improve the temporal resolution of the monitoring practice. If the citrus producers have access to this high temporal and spatial resolution data, they can significantly improve their decision making. HLB Detection Methodology Not only is HLB incurable, but it also has a long latent period that makes it even harder to control and manage. Starch accumulates greatly in HLB-affected leaves (Etxeberria et al., 2009), but it remains invisible for months or even years. When starch accumulation 10
becomes visible, it presents a blotchy mottle on the infected leaf, that might be confused with some nutrient deficiency symptoms. Starch is capable of rotating the polarization of light (Pourreza et al., 2014). A sensing methodology (polarized imaging) was developed based on this optical characteristic of starch at the University of Florida. The sensor was able to detect the HLB-affected trees from healthy, and nutrient deficient trees (Pourreza et al., 2015). The sensor included an inexpensive, but highly sensitive monochrome camera, a set of narrow band high power light-emitting diodes (LEDs), polarizing filters, and a housing. The total cost of sensor components was less that $1,000. The polarized images captured from citrus canopies in different HLB/zinc-deficiency states, had different image intensities and contrasts. A field test in Florida showed that the polarized imaging method could successfully reveal the HLB status of citrus canopies with 97% accuracy (Pourreza et al., 2015). Early HLB Diagnosis The polarized imaging technique was also tested for presymptomatic HLB detection. Citrus trees (2-years old) were graft-inoculated using the disk-graft technique. Timelapse polarized images were acquired from leaves in a weekly manner to investigate how early (after the inoculation) the disease can be detected by the polarized imaging technique. One important impact of using a real-time sensor is an improvement in HLB management by providing high temporal and spatial resolution maps of the spread of the disease in both commercial groves and residential areas. Improved management will lead to sustainable citrus production and the prevention of revenue loss in the California citrus industry. Growers can use the sensor in various ways (aerial, ground, or handheld sensing) based on their preferences and available equipment. Acknowledgement The author of this article would like to give credit to Drs. Wonsuk Lee and Reza Ehsani (University of Florida) and Dr. Eran Raveh (ARO Gilat Research Center, Negev, Israel) for their contributions in the development of the polarized imaging methodology. References: Etxeberria E, Gonzalez P, Achor D, Albrigo G. 2009. Anatomical distribution of abnormally high levels of starch in HLB-affected Valencia orange trees. Physiological and Molecular Plant Pathology, 74(1), 76–83. Pourreza A, Lee WS, Ehsani R, Schueller JK, Raveh E. 2015. An optimum method for real-time in-field detection of Huanglongbing disease using a vision sensor. Computers and Electronics in Agriculture, 110(0), 221¬–232. Pourreza A, Lee WS, Raveh E, Ehsani R, Etxeberria E. 2014. Citrus Huanglongbing detection using narrow-band imaging and polarized illumination. Trans. ASABE, 57(1), 259–272.
CITRUS ISSUES
Supporting CAPCA Since 2006
In Our Next Issue: Impor tant Informatio n and Updates o n Soil & W ater Issues, Inc luding: • Healthy S oils • Nutrients • Soil Mois ture Techn ology ...AND MO RE. Watch for these imp or tan features in our June 2 t 017 Applicator Aler ts publicatio n.
a Insecticides a Soil Treatments a Fungicides a Water Treatments a Herbicides a Bio-Insecticides 1.888.273.3088 | biosafesystems.com
-
®
TWO YEAR CONTROL OF POLYPHAGOUS SHOT HOLE BORER VIA TRUNK INJECTION
NOW AVAILABLE IN CALIFORNIA
Dawn Fluharty, Northwestern Regional Technical Manager 650-996-8291 • dfluharty@arborjet.com • PCA #126831 11
APPLICATOR ALERTS MARCH 2017 / VOL . I1, NO. 1
CITRUS ISSUE Thank you to Bayer CropScience for their sponsorship of this Applicator Alerts issue and their continued CAPCA Platinum Sustaining Membership. (See page 5 for Bayer ACT partnership with Citrus Matters)
CAPCA 2300 River Plaza Dr., Ste 120 Sacramento, CA 95833
APPLICATOR ALERTS