INTEGRATED SUSTAINABLE FRESH CITRUS PRODUCTION SYSTEMS USING PROTECTED AGRICULTURE

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: NEW
• Funding Source: HATCH
• Reporting Frequency: Annual
• Accession No.: 1014802
• Project No.: FLA-CRC-005678
• Project Start Date: Nov 22, 2017
• Project End Date: Oct 31, 2022

Project Director
Schumann, AR, WA.

Recipient Organization
UNIVERSITY OF FLORIDA
G022 MCCARTY HALL
GAINESVILLE,FL 32611

Performing Department
Citrus Research and Education Center

Non Technical Summary
Endemic, incurable Huanglongbing disease of citrus (HLB, "greening") makes it virtually impossible to profitably grow citrus in Florida with conventional grove practices. HLB is associated with the bacterium, Candidatus Liberibacter asiaticus (CLas) and is vectored by the Asian citrus psyllid (ACP, Diaphorina citri). The disease causes general canopy and root decline, asymmetric chlorosis of leaves, and fruit that is discolored, misshapen, drops off prematurely, and is otherwise not fit for sale. This is a particularly dire situation for Florida's fresh citrus fruit growers because those products must maintain cosmetically appealing aesthetics throughout the entire production cycle. In the absence of other solutions for HLB control, some Florida fresh citrus growers are turning to screen house protected agriculture in partnership with UF/IFAS researchers, in order to physically exclude the psyllid insect vector from trees and thus ensure long-term disease-free citrus products. This project addresses the use of and development of sustainable fresh citrus growing systems called "Citrus Undercover Production Systems" (CUPS) based on large protective screen houses using novel integrated pest and disease management technologies combined with accelerated production techniques with high planting densities, selective pruning, hydroponics, automation and mechanization. Outcomes of this research project will be immediately applicable to commercial Florida citrus growers, where more than 90% of citrus trees are HLB-affected and fruit yields are at historical low levels. Other large commercial fresh citrus industries, particularly in California and Texas, will benefit from this research as they are also being impacted by HLB, albeit in the early stages.

Animal Health Component

0%

Research Effort Categories

Basic

15%

Applied

70%

Developmental

15%

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
205	0920	1060	100%

Knowledge Area
205 - Plant Management Systems;

Subject Of Investigation
0920 - Orange;

Field Of Science
1060 - Biology (whole systems);

Keywords

citrus

hlb

psyllid

hydroponics

protected agriculture

robotic scouting

Goals / Objectives
The main goal of the project is to develop sustainable fresh citrus growing systems with protected agriculture in screen houses. Due to the unique growing environment inside a screen house, a new series of challenges which don't exist in the conventional outdoor groves have to be researched and resolved. Novel integrated pest and disease management technologies combined with accelerated production techniques using high planting densities, enhanced pollination, and hydroponics (Fig. 1) are examples. Due to the high planting densities and container culture methods, new effective mechanized methods of weed control, crop spraying and fruit harvesting need to be developed and tested. Frequent effective pest and disease scouting in the CUPS is necessary to enable timely responses and management of pest or disease outbreaks and pressures, but is labor-intensive and expensive to achieve with human scouts. For example, the incidence of citrus greasy spot disease and flower thrips, rust mites and spider mites are exceptionally high in the protected screen house environment and must be adequately controlled to avoid economic damage to the fruit. An automated mechanized scouting technology will be developed to augment human scouts.Specific objectives are:Demonstrate the long-term (7-10 years) sustainable exclusion of ACP, and therefore HLB, from the citrus production blocks grown at the CREC, Lake Alfred, in a 1.3 acre protective screen house and compare with control citrus trees grown outdoors. This is ongoing; weekly insect and mite scouting will be conducted on selected trees in the CUPS and in the outside block using yellow sticky traps and foliage inspections. Pest and disease control sprays will be applied with a motorized greenhouse sprayer as required. Weekly inspections of the screen material will be conducted and any holes or breaches will be repaired. As the screen material ages, some failures must be expected beyond the five year warranty period.Develop and refine a method of whole tree thermotherapy (WTT) for container-grown trees to eliminate HLB disease if and when it appears symptomatically on the canopies. This research is ongoing; preliminary results are available for 'Hamlin' trees treated with steam three years ago to eliminate HLB. Other varieties in the CUPS (murcott, grapefruit, lemon, lime) will be treated and monitored as required. Quarterly PCR analyses will be conducted on leaf tissue samples to monitor the CLas titer over time.Develop long-term recommendations for growing citrus trees hydroponically in containers, including the economics of running such a fresh fruit production enterprise for up to 10 years. This research is ongoing; Citrus trees were planted in a variety of smaller experiments in the CUPS in September 2014, comparing different fresh citrus varieties, rootstocks, container sizes (20, 25, 35 liter volumes), different container designs, two planting densities (871 and 1361 trees/acre), and control trees in the ground. Fruit was harvested in 2016 and will be harvested every year to estimate yields, fruit size, and internal quality over treatments and for the outdoor control trees. We will monitor other economically important variables like the seed count per fruit for Murcott every year to estimate the reduction in seediness when grown in CUPS. In 2017 we will sell the CUPS fruit for the first time, and will use that experience, costs of production, and other economic evaluations to develop economic models for CUPS.Evaluate the efficacy of chemigated neonicotinoid and other systemic insecticides for use in the management of screen house insect pests on potted citrus trees. Develop effective ultra-low volume (ULV) spraying for improving citrus pest control with foliar-applied pesticides and miticides on potted citrus in the screen house environment. A replicated imidacloprid chemigation experiment was conducted for six months, ending January 2017, to quantify and compare the uptake and leaf residue concentrations of imidacloprid in bearing two year old potted Murcott trees (Fig. 1). Treatments are an untreated control and four equal dose imidacloprid applications split differently over time, ranging from every 10 days to every 42 days. Measurements from this experiment are complete and the data will be reported and published in 2017. A second experiment will be started in 2017 to determine the influence of in-vivo imidacloprid photodegradation by sunlight UV radiation. Preliminary data showed an increase in leaf imidacloprid concentration when leaves were shielded from UV light for 10 days after an imidacloprid chemigation application. The new replicated experiment will compare exposed leaves (control: full UV exposure) with leaves covered by UV-blocking optical filter film, kaolinite particle films applied by sprayer, a commercial UV-blocking chemical spray, and covered by 50% screen house mesh fabric. Data from the first and second experiments will provide new guidance for optimizing the efficacy of neonicotinoids for longer term protection of citrus trees against insect pests.Develop robotic autonomous scouting platforms specifically for protected agriculture that will permit very frequent, comprehensive scouting of every tree. A fully autonomous robotic scouting platform will be developed on the framework of a commercial motorized golf caddy. The golf caddy has all the necessary motors, battery power, motor controls and steering mechanisms for rapid development of a scout. The size of the caddy is also smaller than a golf cart, and ideal to navigate the very tight row middles of high density CUPS citrus plantings. We will use an on-board embedded computer loaded with the latest Caffe deep learning software, coupled with digital cameras for navigation and analysis of the tree canopies. The deep learning software utilizes artificial intelligence in order to "teach" the vehicle how to drive correctly though the grove, and how to recognize target pests and diseases. Once the software platform is trained, the deep learning neural network can be deployed autonomously to frequently scout the CUPS and report pest and disease problems.Evaluate and adapt available sickle-bar tree hedging equipment for essential tree size control in CUPS. In 2017 we will begin using a 10-foot long vertical sicklebar hedger blade mounted to a 4-foot wide tractor to hedge and shape the CUPS trees in high density configurations (Fig. 1). We anticipate some learning and adaptation of this technique will be necessary since there is no documented guidance on how best or how frequently to hedge trees in CUPS.Develop an effective screen house cooling method with overhead water sprinklers to prevent sunburn of fruit in summer months, while complying with water use BMPs. This system was tested for the first time in 2016 and completely prevented sunburn of Murcott fruit due to overheating in summer. However in order to comply with water use BMPs and reduce costs, we will add temperature sensors in artificial fruit to selected trees and link them to computerized smart controller software so that the water sprinklers only run when absolutely necessary. Artificial intelligence software will be used for the control logic since it can be trained and can also "learn from experience".Adapt and modify the overhead sprinkler technique for protection of the CUPS trees against freezes. This is an extension of (7) and the sprinkler system is therefore already installed. During freeze events, we will experiment with the best scheduling of the sprinkler system in order to minimize water use while achieving acceptable freeze protection of the citrus in the CUPS.

Project Methods
The main goal of the project is to develop sustainable fresh citrus growing systems with protected agriculture in screen houses. Due to the unique growing environment inside a screen house, a new series of challenges which don't exist in the conventional outdoor groves have to be researched and resolved. Novel integrated pest and disease management technologies combined with accelerated production techniques using high planting densities, enhanced pollination, and hydroponics (Fig. 1) are examples. Due to the high planting densities and container culture methods, new effective mechanized methods of weed control, crop spraying and fruit harvesting need to be developed and tested. Frequent effective pest and disease scouting in the CUPS is necessary to enable timely responses and management of pest or disease outbreaks and pressures, but is labor-intensive and expensive to achieve with human scouts. For example, the incidence of citrus greasy spot disease and flower thrips, rust mites and spider mites are exceptionally high in the protected screen house environment and must be adequately controlled to avoid economic damage to the fruit. An automated mechanized scouting technology will be developed to augment human scouts.

Progress 10/01/19 to 09/30/20

Outputs
Target Audience:Target audience(s) included citrus growers in Florida andCalifornia as the primary end-users, but this research also engages with several other groups including manufacturers,citrus processors, extension agents, crop advisors, farming industries, trade journals, academic/industry researchers, policy makers andstakeholders for other commodity groups. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?The project has providedvisitors opportunities to learn more about the CUPS system with guided tours and a field day. How have the results been disseminated to communities of interest?We presented pertinent research results at multiple Florida grower forums, seminars, workshops and field days using Powerpoint slides, posters, handouts and video clips as support material. Magazine articles were published for citrus grower readers. We also hosted ongoing grower and scientist visits to our CUPS facility and a Field Day at the CREC CUPS on 12 December. We are updateing a project web site at http://www.makecitrusgreatagain.com/CUPS.htm. Please refer to the products section for a complete listing of all the outcomes that have been disseminated in 2019-20. What do you plan to do during the next reporting period to accomplish the goals?We will complete the fruit color break experiment with Ray Ruby and W. Murcott varieties, using different colored screens, and evaluate the results against uncovered controls. The NEW sanitizer experiment will also be continued until harvest in 2020/21 and evaluated for control of greasy spot disease and rust mites. Full harvest data of Ray Ruby grapefruit and Honey Murcott will be collected in Dec/Jan. The Honey murcott plots are evaluating different canopy management strategies. In 2021 we will finalize the prototype testing for robotic pest detection, focusing on performance in the CREC CUPS and possibly in the IRREC CUPS. All routine hedging,pesticide spraying, weed management, and fertigation/irrigationactivities will continue in 2021, which will be the 7th year of the CUPS experiment at the CREC. Linked to the research, we will continue to report the results in journals, news media, trade journals, web sites, grower field days, workshops and personal tours.

Impacts
What was accomplished under these goals? In Florida, there are now approximately 1000 acres of commercial CUPS groves planted, an increase of 100% since 2019. The Dun-D Citrus Growers Cooperative is planning to have up to 1,000 acres of their own CUPS groves very soon (https://www.growingproduce.com/citrus/citrus-achievement-award/up-to-1000-new-acres-of-florida-citrus-going-under-cover/) The 4.7-acre research CUPS at the Lindcove Research and Education Center of the University of California was completed in 2020 and will be planted in the fall. This is the primary CUPS test facility for California. Research/extension activities in 2020 continued with those proposed in this project, focusing on further improving CUPS technology by developing efficient, automated detection methods for ACP, incursions, integrated pest management with biocontrol, horticultural methods such as selective canopy management, hydroponics and sensor-based irrigation, suitable varieties and rootstocks to boost yields, and a comprehensive economic analysis. Horticultural research to improve the fruit color break of some varieties grown in CUPS was continued in 2020 after preliminary promising results in 2019. Our research CUPS at the CREC is 1.3 acres and was started 6.0 years ago. In March 2020 we hired contractors to re-screen both the roof and the walls with new 40-mesh screen because maintenance of the old screen was becoming difficult. A recently completed UF/IFAS study had determined that 40-mesh screen was as effective as 50-mesh screen for ACP exclusion, and 40-mesh should permit more air flow due to the larger mesh apertures (https://academic.oup.com/jee/article/113/4/2026/5840497). The contractors started with the roof, removing and replacing one panel at a time, followed by one wall at a time, thus minimizing the number of CUPS trees exposed to pests outside the structure (especially ACP). During the five months after re-screening, we did not detect any ACP in the CUPS, demonstrating that by careful coordination and planning, the citrus trees inside can remain protected during major renovation work. The original screen had a warranty of five years and lasted six years. We expect screen to last longer than six years if there are no major storm events. The 'Ray Ruby' red grapefruit variety has produced reliably high fresh fruit yields for five seasons in the CUPS. Cumulative yields from the 2015/16 to 2019/20 season reached 2,975 boxes/acre for the US897 rootstock trees growing in 25-L pots, at a spacing of 5'x10' (871 trees/acre). 'Ray Ruby' trees in the CUPS showed no alternate bearing, which is very important for ensuring reliable fruit supplies to markets and steady revenue. In season five (year six since planting), we noticed a 15 to 23% decline in yield from 2018/19 to 2019/20 for the US897 rootstocks. The trees growing in the smallest pots (20 L) were worst-affected, followed by the 25-L and 35-L pots. Trees growing on Sour Orange rootstocks in 35-L pots continued to show increasing yields, but after six years we expect that all the container-grown trees will lose vigor from becoming pot-bound. Declining fruit size was also noticed in 2019/20, and the most severe effects were again seen on the trees growing in the smallest pots. The 2019 summer had a prolonged wet period of at least four weeks in July when it rained nearly every day. The trees could not be properly protected with fungicidal sprays during that critical summer period and the high incidence of greasy spot disease detrimentally affected the percentage pack-out of harvested fruit. The smaller fruit size also reduced final pack-out percentages, with corresponding lower market prices than the larger fruit seen in previous years. As a result, the net fruit revenue for the CUPS grapefruit in 2019/20 was only $9.50 /box, compared with an average of $26 /box in previous years. Despite the lower revenue in 2019/20, the net five-year cumulative fruit revenue for the 'Ray Ruby' grapefruit on US897 rootstock in 25-L pots was estimated at $64,000 per acre. In March 2020, we replanted all the 'Ray Ruby' grapefruit trees in the ground to remedy the yield and fruit size decline caused by the containers. The 'W. Murcott', 'Dancy' and 'Sugarbelle' tangerine and tangerine hybrid varieties in the CREC CUPS were particularly productive in 2019/20. 'W. Murcott' yields were 971 boxes/acre on C35 rootstock, and 1,226 boxes/acre on X639 rootstock, both at a high planting density of 1,361 trees/acre. 'Dancy' yields were 871 boxes/acre and 'Sugarbelle' yields were 895 boxes/acre, both at a planting density of 871 trees/acre. The return fruit set of these varieties in 2020/21 will be low due to alternate bearing, a common problem in high-yielding tangerine varieties. The 'W. Murcott' and 'Dancy' varieties both had favorable brix/acid ratios of 17.7, and acid contents of 0.60% and 0.46%, respectively. 'Sugarbelle' reached a ratio of only 10.7 due to a high acid content of 1.23%. We could not determine the cause for the high acid content, but anecdotal evidence suggests that outdoor groves of 'Sugarbelle' also had unusually high acid levels during this past season. In 2020 we continued research developing more effective remedies for controlling greasy spot disease in the CUPS by using Neutral Electrolyzed Water (NEW), or dilute sodium or potassium hypochlorite sanitizer sprays. The advantage of NEW is that it is cost effective, by being generated from sodium chloride electrolysis conducted on-site, more efficacious than commercial sodium hypochlorite, and avoids transportation of hazardous materials. This year's replicated field experiment aims to fine-tune the application rate and timing to achieve sufficient control of greasy spot disease, while not damaging the development of normal fruit size, color and quantity. The autonomous robotic scouting platform for arthropod pests that uses artificial intelligence and machine vision was improved by incorporating the latest EfficientNet neural networks from Google into the automated smart trap. The smart trap uses ultraviolet LED lights to lure, and capture flying pests that might occur in CUPS (thrips, leaf rollers, aphids, psyllids, whitefly, leaf miner) and then identify them with AI machine vision. In summer/fall 2020 we initiated an experiment to evaluate the effect of different colored shadecloth screens on fruit color development near maturity. We started the first experiment with Ray Ruby grapefruit in August, with individual colored bags (7 different colors), and in October we will repeat the experiment with W. murcott variety.

Publications

• Type: Journal Articles Status: Published Year Published: 2020 Citation: Ebert T.A., Waldo L., Stanton D., Schumann A. (2020) Screen Mesh Size for Exclusion of Diaphorina citri (Hemiptera: Liviidae) in Citrus Production. Journal of Economic Entomology https://doi.org/10.1093/jee/toaa095.
• Type: Other Status: Accepted Year Published: 2020 Citation: Schumann A., Waldo L., Mariner N., TE E. (2020) Five years of fresh fruit production in CUPS, Citrus Industry 101(11): pp.??
• Type: Other Status: Published Year Published: 2020 Citation: Schumann A., Singerman A., Wright A., Ferrarezi R.S. (2020) Citrus Under Protective Screen (CUPS) Production Systems- 2020-2021 Florida Citrus Production Guide EDIS, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL. 2 pp.
• Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Schumann A. (2020) Growing Citrus for the Fresh Market in Covered Production Systems, ASHS, Orlando, FL.
• Type: Other Status: Under Review Year Published: 2020 Citation: Krajewski A., A S., TE E., Oswalt C., Ferrarezi R.S., Waldo L. (2020) Management of citrus tree canopies for fresh fruit production, EDIS, UF, Gainesville, FL. Pp. ??
• Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Ferrarezi R.S., Mixon J., A. S., Krajewski A., Alfarez F., James H., Gil C., Davis D., King C., Locatelli G. (2020) Hand Pruning Increases Fruit Yield and Quality of W. Murcottand SugarbelleMandarins Cultivated Under Protective Screen, ASHS Annual Conference, ASHS, Orlando, FL.

Progress 10/01/18 to 09/30/19

Outputs
Target Audience:We used a diverse portfolio of extension outlets to reach out to our target audience(s). Citrus growers in Florida and California are the primary end-users, but this research also engages with several other groups including manufacturers, citrus processors, extension agents, crop advisors, farming industries, academic/industry researchers, policy makers and stakeholders for other commodity groups. Changes/Problems:IRREC CUPS: A winter storm in early part of 2019 caused significant damage to the roofs of the CUPS at the Indian River Research and Education Center, which most likely allowed Asian citrus psyllid to enter and establish in the CUPS. CUPS were exposed for few months and roofs replaced on all four structures. Changes: 1) A new irrigation and fertigation controller (HI 10000, Hanna Instruments, Woonsocket, RI) was successfully installed in 2019. 2) The sand used as a substrate for the potted trees from years 2013-2019 was replaced by a commercial substrate (Fafard Citrus Mix RSi; Sungro Horticulture, Agawam, MA) on 400 trees. That major task was needed since sand was a poor media that reduced tree growth overtime, leading to reduced growth compared to the in-ground trees. It took approximately 2-3 months to fully accomplish this time-consuming and labor-intensive activity. 3) The irrigation emitters were replaced by two 1 GPH drip emitters per tree. 4) Fertigation started been applied daily for a total of 180 kg N/ha per year using the 15N-4.8P-25.7K water-soluble fertilizer [15% total-N, 4.8% P, 25.7% K, 0.8% Mg, 1.0% S, 0.02% B, 0.05% Cu, 0.1% Fe, 0.05% Mn, 0.0005% Mo, and 0.05% Zn (Agrolution pHLow; Everris NA, Dublin, OH)] and calcium nitrate (15.5% total-N and 19% Ca). Problems:1) In April 2019 a tropical storm destroyed the roof of all screenhouses, requiring complete replacement. The replacement job faced a few setbacks, since the cheapest vendor did not execute the contract on time, and a most expensive vendor had to be hired, pushing the activity completion in several months. The task was completed in October 2019. 2) Our team started evaluating canopy management strategies on a replicated trial in another commercial CUPS location at George Pantuso's operation in Zolfo Springs, FL. We tested four treatments: a control (mechanical pruning - at bloom and late summer), hand pruning (at bloom and late summer), mechanical + hand pruning (at bloom and late summer) and hand pruning (at bloom only) in potted 'W. Murcott' mandarin. However, the grower decided cutting trees down starting early January 2020 and start his CUPS project over again with grapefruit trees since the 'W. Murcott' mandarins were tested positive for HLB due to hurricane damages in 2017 and the low fruit yield/lack of color in 2019/20. 3) The research graduate (a PhD candidate) in charge of implementing several of the project objectives (#4, 4.1, 4.2 and 4.3) was not able to keep up the tasks on schedule. The student was facing personal problems and took a long Summer vacation, being oriented to seek for UF Counseling and Wellness Center support. Unfortunately the student ended up taking a medical leave in the middle of the Fall semester and withdrew UF Graduate Program. Modifications: The installation of trials with different screen colors in two commercial collaborators was not completed due to problems in identifying grower collaborators. One of our long term collaborators (Mr. George Pantuso) cut his CUPS trees down and the other collaborator (Mr. Jerry Mixon) did not want to use more trees of his commercial production for trials. The trial is getting installed at the IRREC CUPS as soon the 2019/20 season fruit is harvested and existing trees hedged and topped. What opportunities for training and professional development has the project provided?Emilie Demard PhD student attended two-week Acarology Summer Program at the University of Arkansas, Fayetteville, AK, which provided training in the identification and classification of mites of agricultural importance and on evolutionary and applied aspects of mite biological control. She and the postdoc Dr. S. Al-Shami were also sent to several meetings where they presented the work being conducted in the CUPS. Presentations on CUPS pests and management issues were made at the professional and grower meetings, which provided the research and extension specialists, students and citrus producers to gain knowledge about the CUPS production system. Presentations are listed in the products section. The project has provided visitors to learn more about the system by guided tours at the IRREC CUPS. The project Co-PI Dr. Ferrarezi and graduate student Natalia Macan were able to visit a CUPS research facility at the Citrus Research Center "Sylvio Moreira" in Cordeirópolis, SP, Brazil, and the Co-Pi Dr. Ferrarezi visited commercial citrus production areas cultivated under screen for hail protection in Alcanar and Valencia, Spain. How have the results been disseminated to communities of interest?We presented pertinent research results at multiple Florida grower forums, seminars, workshops and field days using Powerpoint slides, posters, handouts and video clips as support material. Numerous magazine articles were published for citrus grower readers. We also hosted ongoing grower and scientist visits to our CUPS facility and a Field Day at the CREC CUPS on 12 December. We are developing a project web site at http://www.makecitrusgreatagain.com/CUPS.htm. Please refer to the products section for a complete listing of all the outcomes that have been disseminated in 2019. IRREC CUPS site: Results were published as a peer-reviewed publication in Frontiers in Plant Science (https://www.frontiersin.org/articles/10.3389/fpls.2019.01598/full), and presented at the Florida Society of Horticultural Science's 2019 Annual Conference in Maitland/FL, Sixth International Research Conference on Huanglongbing in Riverside/CA, and, "CUPS, mini-CUPS and other strategies to manage HLB" seminar at the UF/IFAS Southwest Florida Research and Education Center in Immokalee, FL (https://citrusagents.ifas.ufl.edu/newsletters/zekri/Flatwoods%20CitrusDecember%202019.pdf). The seminar occurred on Dec 17, 2019 and hosted approximately 45 participants. LREC: Citrograph article, industry meetings, Rolshausen lab website (), Twitter (@philrols) What do you plan to do during the next reporting period to accomplish the goals?IRREC CUPS: Studies will be conducted to evaluate naturally occurring and commercially available biologicalcontrol agents for their impact on the pests attacking citrus in the CUPS. The evaluations will include exclusion experiments to test the survival, predation or parasitism potentials of the beneficial organisms and open releases of the predators and parasitoids in the CUPS and control. Studies will also be conducted to evaluate the effects of the insecticides and miticides and fungal pathogens against pests colonizing citrus in the CUPS. Findings will be presented at the grower (workshops, field day) and professional meetings and published in the peer reviewed and EDIS documents. Scion and rootstock selection for IRREC CUPS As previously reported, an order was placed with Brite Leaf Nursery (Lake Panasofkee, FL) and trees will be delivered Spring 2020. Varieties ordered (scion and rootstocks): 'Early Pride' on US-942, 'BB-4' on US-897, 'W. Murcott' on UFR-17, 'Minneola' on Kuharske, 'UF-950' on US-897, 'Dancy' on UFR-4, 'Nules Clementine' on UFR-4, 'Bingo' on US-942, 'Ray Ruby' on Sour Orange, 'Ray Ruby' on US-897, 'Ray Ruby' on Kuharske, 'Ray Ruby' on UFR-6, 'Ray Ruby' on UFR-17, 'UF-914' on US-942, 'Navel '56-11'' on UFR-17, 'KinnowLS' on UFR17, 'UF Sunrise' on UFR-17, 'FF-1-75-55' on UFR-17, 'Tango' on UFR-17, 'Page' on UFR-17, 'UF Glow' on UFR-17, 'C4-15-19 (DPI-435-C4-15-21)' on UFR-17, '5-1-99-2 Pummelette (DPI-435-5-1-99-2)' on UFR-17, '1420' on UFR-17, '1424' on UFR-17, 'Persian lime' on Rangpur lime, 'Mandarin DPI-435-0117' on UFR-17, 'Mandarin UF 304' on UFR-17, 'seedless Murcott clone (DPI-435-18A-10-47)' on UFR-17, 'Mandarin DPI-435-304-4-16' on UFR-17, 'Cybrid Dancy (DPI-435-KW-5-7)' on UFR-17, 'Red grapefruit N11-7 (DPI-435-N40-16-11-7)' on UFR-17, 'Cybrid #304 (DPI-435-304-4-16)' on UFR-17, 'Low-seeded cybrid "Furr" 1 (DPI-435-A-32.5)' on UFR-17, 'Low-seeded cybrid "Furr" 2 (DPI-435-N40-18A-10-11)' on UFR-17, 'US HoneyCoat' on UFR-17, 'US Seedless Surprise' on UFR-17, 'FF-1-22-79' on UFR-17. Horticultural improvements to maximize premium-grade fresh fruit production in CUPS: Canopy management We will continue the evaluation of advanced horticultural techniques to increase tree yield by using canopy management strategies on a replicated trial in a commercial CUPS location at Jerry Mixon's operation in Bartow, FL. We are testing four treatments: a control (mechanical pruning - at bloom and late summer), hand pruning (at bloom and late summer), mechanical + hand pruning (at bloom and late summer) and hand pruning (at bloom only) in different mandarins ('W. Murcott' and 'SugarBelle'). Studies were conducted on trees in-ground and in pots. Effect of different screen color and/or reflective mulch on plant growth and fruit yield Literature review was performed by the PhD student, treatments established and two grower collaborators contacted to perform field trials. Jerry Mixon did not accept using more trees from his commercial operation to conduct trials due to the potential impact on yield despite of potential compensation, and George Pantuso cut down all the trees and is replanting. The trial is getting installed at the IRREC CUPS as soon the 2019/20 season fruit is harvested and existing trees hedged and topped. Treatments: T1 (Control): No photoselective net, T2: Red photoselective net, T3: Blue photoselective net, T4: Gray photoselective net. Sensor-based precision irrigation and fertigation control for optimized fruit production Start of the treatment application. Treatments on Trial 1 (irrigation): two environments (open-air and screenhouse), two planting methods (in-ground and potted) and three Irrigation scheduling (T1 based on ETo, T2 and T3 based on VWC). Treatments on Trial 2 (fertigation): two environments (open-air and screenhouse), two planting methods (in-ground and potted) and three fertilization treatments (T1 control, T2 and T3 based on EC). We will continue with routine maintenance, spraying, harvesting, irrigation, fertilization, leaf sampling and data analysis in the CUPS. The screen house will be re-screened in early 2020. A second field experiment with the NEW sanitizer spray will be conducted in 2020 to suppress greasy spot, melanose and scab fungal diseases on grapefruit. The goal will be to refine the application rate to be effective for disease control but safer on the citrus trees than it was in the 2019 season experiments. Prepare a journal paper to publish the 2019 results of the NEW experiments. The robotic scouting platform will be retrofitted with a new automatic insect trap using deep learning machinevision to detect different insects in real time. The performance of the robotic scouting platform will be evaluated in the CREC CUPS as proof of concept. Continue evaluating the grapefruit and tangerine varieties in the CUPS to maximize fresh fruit quality and quantity at early, mid and late seasons. The multi-year canopy management / pruning experiments in Honey Murcott will be continued. Additional gibberellic acid spray trials will be initiated at bloom to improve fruit set on Early Pride, Sugar Belle, and Dancy varieties in particular. Based on color-break tests with W. Murcott and UF914 using LED light wavelengths and colored shadecloth in 2019, we will expand the tests to include other varieties and combinations of spectral filters and timings to improve fruit rind color at maturity. Continue refining the economic analysis of CUPS fresh fruit production as new data becomes available. Host a CUPS field day in Florida and California. Publish pertinent outcomes in trade journals, EDIS documents, and web sites. Present results at grower forums like the Citrus Expos in Florida and California. Host visits with growers in the CUPS as needed. Visit commercial CUPS in Florida and California to provide logistical and scientific support.

Impacts
What was accomplished under these goals? In Florida, there are now approximately 500 acres of commercial CUPS groves planted, an increase of 66% since 2018. Additional new CUPS projects and expansion of existing sites in Florida will add hundreds more acres in 2020. A 4.7-acre research CUPS being built at the Lindcove Research and Education Center in late 2019 will be planted in 2020 and serve as the primary CUPS test facility for California. Research/extension activities in 2019 continued with those proposed in this project, focusing on further improving CUPS technology by developing efficient, automated detection methods for ACP incursions, integrated pest management with biocontrol, horticultural methods such as selective canopy management, hydroponics and sensor-based irrigation, suitable varieties and rootstocks to boost yields, and a comprehensive economic analysis. Horticultural research was initiated in 2019 to improve the fruit color break of some varieties grown in CUPS. The W. Murcott variety produces high yields of seedless fruit in CUPS, with excellent internal quality, but the external peel fails to color properly and reduces its consumer acceptance and therefore the market price. CREC CUPS: Our research CUPS at the CREC is 1.3 acres and was started 5.5 years ago. During that time we found only one psyllid in the screen house and in October 2019 we found and verified the first HLBpositive tree, representing an HLB-incidence of only 0.09% over 5.5 years. Fruit yields in the CUPS, especially grapefruit, have proved to be reliable and high. Cumulative harvested red grapefruit yields reached 2,950 boxes/acre in December 2019, worth more than $76,000/acre at current fresh fruit prices. An economic analysis of 4 grapefruit seasons in our CUPS, projected out to 10 years showed it would be profitable with a decent return on investment of around 15% if projection assumptions hold. We are evaluating about 20 different citrus varieties in the CREC CUPS in order to support the commercial CUPS growers with the best possible information and choices. Variety evaluations in 2019 included scoring seediness of the fruit, increasing fruit set with gibberellic acid sprays, investigating mid-season fruit splitting, and testing canopy management options and their effects on fruit yields and quality. Discussion was also initiated on the incidence of "open navels" in certain hybrid and/or mandarin cultivars, and its effects on the incidence of certain important fungal pathogens, such as Alternaria citri (or A. alternata?) core rot. We made good progress with developing more effective remedies for controlling greasy spot disease in the CUPS by using Neutral Electrolyzed Water, or dilute sodium or potassium hypochlorite sanitizer sprays. The greasy spot lesions on the leaves were significantly reduced and trees retained their leaves for longer in treated plots. Unfortunately the yields and fruit size were significantly reduced by the sanitizer, which we hope to resolve with follow-up experiments in 2020. Other important fruit quality issues that occur in CUPS are being actively researched and some progress was made in 2019. The W. murcott variety is popular in CUPS because it is seedless, easy peeling and high yielding. In the Florida climate and particularly in CUPS, it fails to color up properly at maturity, which reduces its value at markets. Standard ethylene degreening also fails to work on W. murcott. We ran six post-harvest experiments with LED lights of ten different wavelengths to determine that red and pink (=blue+red) lights have a strong positive effect on degreening W. murcott fruit, even in the absence of ethylene. In 2019 we made more progress with developing an autonomous robotic scouting platform for arthropod pests that uses artificial intelligence and machine vision. We have nearly completed an automated smart trap for capturing and identifying any of the flying pests that might occur in CUPS (thrips, leaf rollers, aphids, psyllids, whitefly, leaf miner). IRREC CUPS: Objective 1: Refer to the PDF file in the link https://www.dropbox.com/s/pv2r4pfx0ufrstt/PDF2019.pdf?dl=0 (8000 character limit in this section has been exceeded) Objective 3: Scion and rootstock selection for IRREC CUPS Trees were ordered at Brite Leaf Nursery (Lake Panasofkee, FL) and are expected to be delivered/planted in Spring 2020.We kept constant communication with nursery and UF breeders to check order status, assist with budwood and seed supply and update the variety list as needed. Objective 4: Horticultural improvements to maximize premium-grade fresh fruit production in CUPS 4.1 Canopy management Our team continued evaluating advanced horticultural techniques to increase tree yield by using canopy management strategies on a replicated trial in two commercial CUPS locations at George Pantuso's and Jerry Mixon's operation in Zolfo Springs, FL and Bartow, FL, respectively. Second year of fruit yield data is been collected and processed. 4.2 Effect of different screen color and/or reflective mulch on plant growth and fruit yield Literature review was performed by the PhD student, treatments established and two grower collaborators contacted to perform field trials. Mr. Jerry Mixon did not accept using more trees from his commercial operation to conduct trials due to the potential impact on yield despite of potential compensation, and Mr. George Pantuso cut down all the trees and is replanting. We are implementing the trial at the IRREC CUPS. 4.3 Sensor-based precision irrigation and fertigation control for optimized fruit production A new irrigation and fertigation controller was installed in early 2019. A new irrigation and fertigation system was designed and installation completed late in 2019, with miles of trenches excavated and pipes and wires deployed in the field. Independent solenoid valves and soil moisture sensors were connected to dataloggers, multiplexers and relay drivers. The communication between the loggers and a central computer was established using radio modules, and the computer was connected to the internet by a local hotspot. Objective 6: Develop decision support guidelines for CUPS A "CUPS, mini-CUPS and other strategies to manage HLB" seminar was organized at the UF/IFAS Southwest Florida Research and Education Center in Immokalee, FL (https://citrusagents.ifas.ufl.edu/newsletters/zekri/Flatwoods%20CitrusDecember%202019.pdf) with approximately 45 participants. A refereed publication in Frontiers in Plant Science provided research results of a long-term experiment at the IRREC CUPS (https://www.frontiersin.org/articles/10.3389/fpls.2019.01598/full).

Publications

• Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Ebert, T., L. Waldo, W. Holmes, N. Mariner and A.W. Schumann (2019). Phytotoxicity Threshold for Neutral Electrolyzed Water in Citrus. Florida State Horticultural Society Annual Meeting, Sanford, FL, ASHS
• Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Ebert, T., L. Waldo, D. Stanton and A. W. Schumann (2019). Screen mesh size selection for exclusion of Diaphorina citri (Hemiptera: Liviidae) in citrus production. Entomology 2019, ESA.
• Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Schumann, A., L. Waldo, W. Holmes, E. TE, N. Mariner, G. Test and A. Krajewski (2019). Hydroponically-grown grapefruit maximize HLB-free fresh fruit production in CUPS. IRCHLB. Riverside, CA.
• Type: Journal Articles Status: Published Year Published: 2019 Citation: FERRAREZI, R. S.; QURESHI, J. A.; WRIGHT, A. L.; RITENOUR, M. A.; MACAN, N. P. F. 2019. Citrus production under screen as a strategy to protect grapefruit trees from huanglongbing disease. Frontiers in Plant Science. 10(1598): 1-16. DOI: https://doi.org/10.3389/fpls.2019.01598
• Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: FERRAREZI, R. S.; HERNANDEZ, Y. V.; STEPHENS, J. 2019. Environmental parameters inside the citrus under protective screen system for fresh grapefruit production. Florida Society of Horticultural Science, 2019 Annual Conference (Abstr.). Maitland/FL.
• Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: FERRAREZI, R. S.; QURESHI, J. A. 2019. Citrus Under Protected Screen (CUPS) for grapefruit production in Floridas East Coast. Sixth International Research Conference on Huanglongbing, 2019 Annual Conference (Abstr.). Riverside/CA.
• Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: DEMARD, E. P.; DOKER, I.; FERRAREZI, R. S.; QURESHI, J. A. 2019. Pest and predacious mite complex of Citrus Under Protective Screens (CUPS). Florida Entomological Society, 2019 Annual Meeting July 21-24, 2019 (Abstr.). Jupiter/FL.
• Type: Other Status: Published Year Published: 2019 Citation: DEMARD, E. P.; FERRAREZI, R. S.; QURESHI, J. A. 2019. Abundance and distribution of the citrus rust mite (Phyllocoptruta oleivora) and the citrus red mite (Panonychus citri) in Citrus Under Protective Screens (CUPS). TREC South Florida Graduate Research Symposium (Abstr.). Homestead/FL.
• Type: Websites Status: Under Review Year Published: 2019 Citation: http://www.makecitrusgreatagain.com/CUPS.htm
• Type: Other Status: Published Year Published: 2019 Citation: Rolshausen, P., G Barry and A Schumann (2019). Growing citrus under nets. Citrograph. Visalia, CA, Citrus Research Board. Winter 2019: 40-43.
• Type: Other Status: Published Year Published: 2019 Citation: Schumann, A., A. Singerman and Y. Wang (2019). Production, consumer preference, and economics of fresh grapefruit grown in CUPS. Citrus Industry 100(11): 14-18.
• Type: Other Status: Published Year Published: 2019 Citation: Schumann A., Singerman A., Wright A., Ferrarezi R.S. (2019) Citrus Under Protective Screen (CUPS) Production Systems- 2019-2020 Florida Citrus Production Guide EDIS, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL. 2 pp.

Progress 11/22/17 to 09/30/18

Outputs
Target Audience:We used a diverse portfolio of extension outlets to reach out to our target audience(s). Citrus growers are the primary endusers, but this research also engages with several other groups including manufacturers, screen house builders, extension agents, farming industries, packing houses, academic/industry researchers, policy makers and stakeholders for other commodity groups. Principal locations of target audiences are in Florida and California, but recently other citrus-producing states like Alabama have requested information from us. Changes/Problems: Hurricane Irma caused significant structural damage to the CUPS screen houses at CREC and IRREC, and about four months of dedicated time were required to conduct the required repairs, which were still ongoing in 2018. Damage to the IRREC CUPS structures allowed the entry of psyllids until repairs were completed. At the CREC CUPS, damaged screen was quickly patched to prevent psyllid entry and none were detected in the CUPS during 2018. At the CREC site, the whole-tree thermotherapy method was becoming rapidly unviable due to the constant prolific psyllid pressure and re-inoculation of thermotherapy-cured trees in the outdoors. This outcome prompted us to phase out this objective, beginning in the 2018/19 season. What opportunities for training and professional development has the project provided?IRREC CUPS site: A PhD student was hired to work on understanding the mite problems and management in the CUPS. She monitored populations of pest and beneficial mites biweekly in CUPS and respective outside controls and presented the findings at Florida Entomological Society and Entomological Society of America meetings. She also presented her PhD research proposal seminar in Fall 2018. These events were attended by students and research and extension specialists. A temporary assistant was hired to help with the monitoring and management of Asian citrus psyllid (ACP), citrus leafminer (CLM), mealybugs, scales and beneficial organisms initiated in 2018. Beside ACP and CLM monitoring using sticky cards, he is also helping with comparisons of tap sampling and suction sampling methods and releases of the parasitoid Tamarixia radiata conducted in the CUPS and outside. A full-bright scholar from Philippines was invited to the lab and she is working on the investigation against Florida red scale an important pest of citrus in protected and open systems. A commercially available parasitoid Aphytis melinus and naturally occurring species are being tested against Florida red scale. The Citrus Horticulture Laboratory team visited the CREC CUPS twice in 2018, and hosted multiple tours for growers and visitors at the IRREC CUPS. The previous PhD candidate sponsored by the grant attended a training about using the LI-6400XT photosynthesis gas analyzer at Licor (Lincoln, NE), and was leading an independent trial to use sap flow sensors in citrus trees that was going to be useful for measuring water uptake on CUPS trees. CREC CUPS site: An indoor workshop with Powerpoint and handouts on CUPS canopy management, was held twice in November at the CREC for stakeholders: "Canopy management for CUPS", by Dr. Andrew J. Krajewski, our project consultant from International Citrus Technologies Pty Ltd, Albany, Western Australia. How have the results been disseminated to communities of interest?We presented pertinent research results at multiple Florida grower forums, seminars, workshops and field days using Powerpoint slides, posters, handouts and video clips as support material. Numerous magazine articles were published for citrus grower readers. We also hosted ongoing grower and scientist visits to our CUPS facility. There are more than ten growers / groups currently that are seriously planning to establish similar larger covered growing systems for fresh fruit. They have consulted repeatedly with us for advice and to view our own progress with the system. There is increasing interest in the CUPS system among the FL fresh citrus growers, with about 250 acres of commercial CUPS in progress during 2018 and more acres of new CUPS structures planned for construction in 2019. An annual CUPS field day was held by Arnold Schumann, Chris Oswalt, and Timothy Ebert on November 15, 2018. The event was co-hosted by KLM Farms commercial CUPS, one of the grower-stakeholders with 35 acres of CUPS (to be expanded to 75 acres in 2019): A comprehensive video was produced by PGTV - Polk TV, and can be watched at: https://www.youtube.com/watch?v=ksxWYM8u_TY For a list of outreach activities and materials in 2018, see "Other Products". A web site for the CUPS research is under development at http://www.makecitrusgreatagain.com/CUPS.htm What do you plan to do during the next reporting period to accomplish the goals?CREC CUPS site: 1. Test dilute potassium hypochlorite sprays in CREC-CUPS to determine efficacy on controlling greasy spot disease 2. Continue to monitor pest populations to work out phenology specific to CUPS. 3. Introduce some predators into CREC-CUPS for mite and thrips control. 4. Submit the screen test results for publication. 5. Study shading and cooling to identify trigger for color development of grapefruit. This is critical information to facilitate color development to take advantage of Christmas sales. 6. Work at machine learning and vision for identifying pest problems in citrus and to complete the autonomous scouting drone. 7. Release other natural enemies in an attempt to find compatible species. 8. Conduct routine maintenance, spraying, harvesting, irrigation, fertilization, leaf sampling and data analysis in the CUPS 9. Conduct the first comprehensive economic analysis of grapefruit and mandarin varieties growing in the CREC CUPS IRREC CUPS site: Dr. Salman Al-Shami is hired as a post-doctoral associate, to work on the research and extension of monitoring and management of multiple pest problems in CUPS. Dr. Al-Shami will be joining the lab in February 2019. He will work on the monitoring of ACP, CLM, mites, scales, and thrips in the CUPS and respective outdoor controls and their management using insecticides and biological control agents. The student will be sampling conventional, organic and untreated citrus groves to identify potential predators for use in CUPS. She will also initiate investigations on potential of a commercially available predatory mite, Amblyseius swirskii, against pest mites of CUPS. Findings of the research will be presented at professional and grower meetings and at CUPS grower field day to be organized in collaboration with the Citrus Horticulturist. 1. An on-demand irrigation system controlled by soil moisture sensors has been designed and will be installed by March 2019 2. Implement the new irrigation system for the irrigation/fertigation management study 3. Improve irrigation and fertigation management 4. Potting media is being switched from a sand to an organic substrate (peat: perlite) 5. Install study with different screen colors in two commercial collaborators

Impacts
What was accomplished under these goals? Impacts: At the time this project proposal was conceived, CUPS proof of concept research was already underway at two REC locations in Florida. CUPS is a readily available technology that can be immediately adopted by growers to revitalize the Florida citrus industry and prevent the California citrus industry from reaching a similar stage of decline. In Florida, there are now approximately 300 acres of commercial CUPS groves planted. Our preliminary results suggest that the productivity per acre for high quality fresh fruit in CUPS can be as much as 16x the productivity from conventional open-air HLB-affected groves. Therefore the relatively small acreage under CUPS can achieve a disproportionately large impact on saving the fresh fruit industry (growers, packing houses, export markest, and associated contracters, agricultural suppliers, etc). Impacts from our research were demonstrated as changed knowledge and actions in the Florida citrus industry. New industry CUPS initiatives were created (http://dun-d.com/citrus-under-protective-screen/), (https://www.growingproduce.com/citrus/growing-under-cover-abig-deal-for-florida-citrus/), (http://www.precisioncitrus.com/), creating new opportunities for employment, sustained fresh citrus production, and optimism for surviving the HLB threat. The smaller Alabama citrus industry is now also impacted by HLB and is looking to use CUPS technology for protecting their trees (one unconfirmed report of their first CUPS structure was received). Regardless of location, CUPS technology is being adopted as an interim, working solution for growing fresh citrus in HLB-affected regions of the USA. Achievement of overall goals: During the past year we have evaluated two promising prototypes for fresh fruit growers; protected agriculture (screen houses), and whole-tree thermotherapy of container-grown citrus. Both alternatives are being tested at the CREC field site. The outdoor grown trees fared well in the previous two years but succumbed to rampant HLB incidence from 2017 (year three), concomitant with plummeting yields. The thermotherapy option will only work if new HLB incidence can be restricted to less than 5-10% per year, and so far that has not been possible. Significantly, the whole-tree thermotherapy method does cure the HLB disease 100%, as we demonstrated by moving some of the treated trees to the psyllid-free sdcreen house. They became HLB-negative (by PCR testing and lack of symptoms) after 3-6 months and have remained healthy. The reason that the method is not viable outdoors is purely a function of the high psyllid incidence, which cannot be adequately controlled. The screen house option looks the most promising at this time, due to the complete exclusion of the psyllid insect vector of HLB disease from the trees. The whole-tree-thermotherapy option requires more breakthroughs in research and development to be a sustainable long-term system. Our research prototype of growing citrus trees hydroponically at high densities in artificial media with pots is proving to be very productive, and many growers are ready to start similar larger systems commercially because they see the same benefits as tomato and other vegetable growers did years ago when they moved to intensive hydroponics in protected greenhouse environments. Inside the CREC CUPS facility, the trees have remained psyllid- and HLB-free for 4.5 years, and cumulative harvested red grapefruit yields reached 2,100 boxes/acre, worth more than $50,000 at current fresh fruit prices. The tangerine 'Honey' murcott variety has also yielded well (~1,500 boxes/acre cumulative) in the CUPS but tends to bear fruit in an alternating habit. Significantly, the packing house handling our fruit sales in 2018 reported a 100% packout for both murcott and grapefruit varieties. In the presence of HLB, Florida fresh fruit packouts are rarely higher than 50%. Our research prototype of growing citrus trees hydroponically at high densities in artificial media with pots is proving to be very productive, and many growers are ready to start similar larger systems commercially because they see the same benefits as tomato and other vegetable growers did years ago when they moved to intensive hydroponics in protected greenhouse environments. The construction of an autonomous robotic scouting platform for arthropod pests that uses artificial intelligence and machine vision (Objective 5) progressed well. We designed and built the autonomous electric vehicle platform, with two DC electric motors for driving and steering, 200-watts of solar panels for electrical self-sufficiency, and trained an artificial neural network for recognizing CUPS rows and drive middles for autonomous navigation with video cameras and GPS. Construction of electronic insect traps for onboard use is also underway, so that the scouting machine can quantify the pests it finds in the CUPS. We are exploring using LED lights of different colors to attract different target pests. We continued to evaluate the 15 commercial fresh citrus varieties in the CREC CUPS, and planted a few 'Minneola' trees in 2018. There are also other experimental, unreleased varieties and rootstocks being evaluated, including UF914 and Bingo (UF Fast-track program). In 2018 (4 years after planting), 'Ray Ruby' grapefruit on both US897 and Sour Orange rootstocks was the top performer overall, with consistent, high yields (2,100 boxes/acre cumulative). We established a new replicated Murcott canopy management experiment in 2018 under Objective 4, comparing manual pruning with machine topping in four treatments. Murcott trees can have excessive vegetative vigor, particularly at high planting densities, and the excess growth must be properly managed to ensure high, consistent yields. In 2018 we also conducted a fruit thinning trial on murcott trees to improve fruit size and revenue. Branch bending (and tying) as an alternative to branch cutting for canopy management was also tested in 2018, with good results. Pertinent CUPS research results were presented at multiple grower forums, seminars, workshops and field days. Most significantly, a CUPS field day attended by about 45 stakeholders was jointly hosted by UF/IFAS and KLM Farms at the commercial CUPS in Alturas, FL on November 15, 2018 (see link to the field day video: https://www.youtube.com/watch?v=ksxWYM8u_TY). We also hosted ongoing grower and scientist visits to our CUPS facilities. In 2018 there were more than ten growers / groups and packing houses that were seriously planning to establish similar larger covered growing systems for fresh fruit. They have consulted repeatedly with us for advice and to view our own progress with the CUPS system. There is increasing interest in the CUPS system among the Florida fresh citrus growers, with about 250 acres of commercial CUPS in progress during 2018, and more acres (likely doubling of Florida acreage) of new CUPS structures planned for construction in 2019 and beyond. Please refer to the "Other Products" section for a full list of extension / outreach events in 2018

Publications

• Type: Other Status: Published Year Published: 2018 Citation: Schumann, A. W., T. E. Ebert, L. Waldo, W. Holmes, N. Mariner, G. Test, C. Oswalt, R. S. Ferrarezi and R. Lesmes (2018). Research update: citrus under protective screen. Citrus Industry. Ocala, FL, Southeast Agnet. 99: 14-19. URL: http://citrusindustry.net/2018/11/26/research-update-citrus-under-protective-screen
• Type: Other Status: Published Year Published: 2018 Citation: Schumann, A. W., L. Waldo, W. Holmes, G. Test and T. E. Ebert (2018). Artificial intelligence for detecting citrus pests, diseases and disorders. Citrus Industry. Ocala, FL, Southeast Agnet. 99: 6-10.
• Type: Other Status: Published Year Published: 2018 Citation: SCHUMANN, A. W.; SINGERMAN, A.; WRIGHT, A. L; FERRAREZI, R. S. 2018. Citrus Under Protective Screen (CUPS) Production Systems. p.79-80. In: ROGERS, M. E.; DEWDNEY, M. M.; VASHISTH, T. (Ed.). 2018-2019 Citrus Production Guide. Lake Alfred, FL: UF/IFAS, 168 p. URL: https://crec.ifas.ufl.edu/extension/pest/PDF/CUPS.pdf
• Type: Other Status: Published Year Published: 2018 Citation: FERRAREZI, R. S. 2018. Growing citrus under enclosures. UC Berkeley Research Snapshot 04/28/2018. URL: https://berkeley.box.com/shared/static/swyx5cv21fakjjmihzdigrpy0nd5u281.pdf
• Type: Other Status: Published Year Published: 2018 Citation: SCHUMANN, A. W.; WALDO, L.; KADYAMPAKENI, D. M.; FERRAREZI, R. S.; OSWALT, C. 2018. Using soil moisture sensors for citrus irrigation. Citrus Industry 10/07/2018. URL: http://citrusindustry.net/2018/07/10/using-soil-moisturesensors-for-citrus-irrigation
• Type: Other Status: Published Year Published: 2018 Citation: Rolshausen, P.E. 2018. Citrus Undercover Production System (CUPS). Citrograph, Spring Issue; p20.
• Type: Other Status: Published Year Published: 2018 Citation: Demard, E. P., and J. A. Qureshi. 2018. (talk) Composition, Abundance and Distribution of Phytophagous Mites in Citrus Under Protective Screens (CUPS). Annual Meeting of the Florida Entomological Society, St. Augustine, FL, July 22-25.
• Type: Other Status: Published Year Published: 2018 Citation: Demard, E. P., and J. A. Qureshi. 2018. (poster) Incidence of Mite Pests on Citrus Under Protective Screens (CUPS). Annual Meeting of the Entomological Society of America, Montreal, Canada, November 10-15.