Grant Information
| Knowledge Area | Subject of Investigation | Field of Science | Percent |
|---|---|---|---|
| 102 - Soil, Plant, Water, Nutrient Relationships | 110 - Soil | 1010 - Nutrition and metabolism | 100% |
Florida citrus production accounts for over 60% of national production. Profitable citrus production on Florida sandy, well drained soils depends on a consistent and reliable water supply for irrigation. The South Florida Water Management District (SFWMD) projects that irrigation water demand will increase 27% by 2020 compared to 20 years ago. This calls for careful evaluation and planning of current and future water needs across the state. The problem of water supply is further compounded by excessive use of fertilizers and other agrochemicals in citrus production which may impact water quality. Thus, successful and commercially profitable citrus production will require judicious management of water and nutrients. Use of improved nutrient management approaches such as fertigation, controlled release fertilizer, split fertilizer applications, use of organic amendments, and avoiding fertilizer applications during Florida's rainy season (between mid-June and mid-September) have been key best nutrient management practices for citrus. To improve water use, use of evapotranspiration-based and soil moisture-based irrigation scheduling are critical best water management practices to avoid under- or over-irrigation. Careful irrigation scheduling coupled with optimal nutrient management would conserve water and reduce water quality impacts by minimizing production costs such as fuel expenses and fertilizer inputs in citrus production systems.
Objective 1. Develop and implement sustainable strategies that optimize water management for citrus production, conservation of water, maximization of tree productivity and minimization of water quality degradation;We will evaluate three N fertilizer rates including: IFAS recommendation for bearing and nonbearing trees (Obreza and Morgan, 2008), 75% of IFAS recommendation and 125% of IFAS recommendation with P and K fixed with respect to N, and also three K rates as follows: IFAS recommendation for bearing nonbearing trees (Obreza and Morgan, 2008), 75% of IFAS recommendation and 125% of IFAS recommendation with P and N fixed with respect to K. Three irrigation rates, 100% evapotranspiration (ET), 75% ET and 50% ET will be used and trees will be irrigated daily. This will be a 3 x 3 factorial experiment replicated 4 times in a randomized complete block design. Soil samples will be collected twice during the year to analyze for pH, electrical conductivity, extractable ammonium and nitrate-N, P and K. Soil samples will be extracted with 2 M KCl (Hanlon et al., 1997) and ammonium-N and nitrate-N will be analyzed using a flow analyzer (QuikChem 8500, Lachat Instruments) at 660 and 520 nm, respectively (Harbridge, 2007a, 2007b). Mehlich-3 extraction will be used for the determination of P and K (Hanlon et al., 1997). All Mehlich-3 sample extracts will be analyzed by inductively coupled plasma-atomic emission spectrometry (Munter et al., 1984). Electrical conductivity and soil pH will be determined using standard methods (Hanlon et al. 1997). Leaf nutrient concentrations will be determined quarterly (Obreza and Morgan, 2008). Tissue N concentration (%) will be determined using the NA2500 carbon (C)/N Analyzer (Thermoquest CE Instruments; ThermoQuest Corporation, Thermo Fisher Scientific Inc., Waltham, MA, USA) and compared with critical N levels for Florida Citrus (Obreza and Morgan, 2008; Obreza et al., 1999; Kadyampakeni et al., 2016). Tissue P and K concentration will be determined using the dry ash combustion digestion method (Anderson and Henderson, 1988). The data collected will be subjected to multi-variate statistical analyses using SAS to establish effects of fertilization and irrigation rates on water quality, soil nutrient content and nutrient uptake of citrus trees. Citrus fruit yields per tree will be estimated annual to determine the effect of fertilization and irrigation treatments. Water samples will be collected bi-weekly using suction lysimeters for nitrate, orthophosphate and pH analysis. Water samples from the plots will be collected using suction lysimeters at 6, 12, 18, and 30-inch depths to estimate nutrient retention capacity and leaching of fertilizer applied as a result of fertilization and irrigation methods (Soil moisture Corp., Pullman, WA). The water samples will be analyzed for nitrate using flow injection analysis systems (Harbridge, 2007a), and for orthophosphate P with colorimetry, while pH will be determined using standard methods (Hanlon et al. 2007). Soil moisture will be monitored continuously using soil moisture sensors commercially available in the US such as HS-10 from Decagon Inc, Pullman, WA at 6, 12, 18, and 30-inch depths. Tree water use will be evaluated using the non-destructive sap flow Dynagage technique (Dynamax Inc., Houston, Texas) (Kadyampakeni et al. 2014b). Leaching fluxes, estimated from soil moisture contents and hydraulic conductivity using Darcy's equation, will be estimated to establish the relations between irrigation rates and soil moisture content and tree performance. Leaf area will be determined using a portable leaf area meter (Model LI-3000A LI-COR, Lincoln, NB). Leaf area index (LAI) of each tree for each plot will be measured using a SunScan canopy analysis system (Dynamax Inc., Houston, TX) during a sunny day.Objective 2. Develop local and regional water use models taking into consideration citrus planting systems, tree water requirements, irrigation scenarios, and water use for cold protection.Data will be collected for calibration and development of water use models for irrigation decision support. Existing models that will be used for piloting water use studies include HYDRUS2D, Root Zone Water Quality Model II (RZWQM2), and Citrus Water Management System (CWMS).Objective 3. Apply precision agricultural technologies for local and regional water management.This will use variable rate fertilizer management through grid or zone sampling to determine the variability of the farmland soil fertility and fertilizers at variable-rates will be applied onto each of those grids or zones (Zaman et al. 2005). Similarly soil moisture-based irrigation schedules would be developed according to the soil hydraulic properties of each zone and tree size. Thus, field performance per unit area could be mapped, tracked and analyzed for growers to know how poorly or well each zone is producing citrus. Analytical procedures for nutrients will be the same as described above while soil moisture (Decagon Inc., Pulman, WA) and plant sensors (Dynamax, Houston, TX) and weather stations (Davis Instruments, Hayward, CA) will be deployed to evaluate irrigation system performance and crop water use.Objective 4. Develop best management practices for water conservation and quality maintenance for surface and ground water sources.This will be achieved through water quality monitoring as explained in Objective 1 and also recording water volumes applied to citrus plantings. Further, intensive, frequent irrigation practices coupled with fertigation using microsprinkler and drip irrigation systems, and advanced irrigation management including regulated deficit irrigation (RDI) and/or alternate partial root zone drying (APRD) will be evaluated to determine the potential water savings and nutrient use efficiency, assess production costs and tree productivity in citrus infected with citrus greening. Data to collect will include fruit yields, production costs and quantity of water used.
Target Audience
The target audience for my programs are citrus growers, extension agents, state specialists, certified crop advisors, consultants, fertilizer retailers and suppliers. My programs deliverscience-based knowledge to people through formal or informal educational programs through classroom instruction, laboratory instruction, or practicum experiences; development of curriculum or innovative teaching methodologies; internships; workshops; experiential learning opportunities; field days, extension and outreach. We also reach out to clientele through blogs, trade journal articles and refereed journal articles.
Changes / Problems
We had major set back as a result of COVID-19 in 2020 and 2021. We fell behind on data collection but now with the vaccines being administered, everything is under control.
Training & Professional Development
We conducted several in-service training workshops in the past 5 years and educated growers, companies, students and certified crop advisors on the importance of proper irrigation management, optimal fertilization and environmental sustsinability.
Dissemination Streams
We disseminated the results through refereed journal articles, trade journals, workshops, in-service trainings, zoom webinars and grower field days.
Next Reporting Steps
Nothing Reported
Target Audience
The target audience for my extension programs are citrus growers, extension agents, state specialists, certified crop advisors, consultants, fertilizer retailers and suppliers.
Changes / Problems
In 2020, this was the year when we struggled with COVID-19 and we had to make changes in personnel and field operations due to the lockdown which adversely affected our data collection schedule. That's the reason this report was not submitted in time.
Training & Professional Development
We provided continuing education units to certified crop advisors and also knowledge through guest lecturers in Advanced Citriculture and Environmental Nutrient Management.
Dissemination Streams
We disseminated the results through workshops, trade journal articles, refereed journal articles and social media.
Next Reporting Steps
We will continue with field experiment, outreach and publication of results so our clientele can access our information. <br><br>
<br>What was accomplished under these goals? We published 12 journal articles, more than 8 trade journal articles and provided several grower talks and informative tools to help growers save water and nutrients. <br><br><b>Publications</b><br>
Target Audience
During this reporting period, we reached out to growers, students and other citrus industry players. Due to COVID-19 restrictions, we mainly reached out via zoom and TEAMS.
Changes / Problems
We had issues with COVID-19 that restricted our work effort, we missed two field harvests. However, this will not affect out reporting requirements,
Training & Professional Development
The project provided several training opportunities for certified crop advisors and extension agents in person face-to-face meeting, zoom and TEAMSformats. We covered topics on best management practices and effective nutrient management. Several participants reported about 13 to 14% increments in knowledge.
Dissemination Streams
We disseminated the results through virtual meetings, zoom webinars, TEAMS meetings and blogs and trade journal articles.
Next Reporting Steps
We will continue doing field experiments, delivering talks, writing extension publications and seeking grant funding to maintain our program. <br><br>
<br>What was accomplished under these goals? Under the above goals, we published a several refereed papers inscientific journals and published one book. One graduate student completed his studies. Also, one project was completed and a new project was funded and will start in 2021. <br><br><b>Publications</b><br>
Target Audience
The target audience for my programs are citrus growers, extension agents, state specialists, certified crop advisors, consultants, fertilizer retailers and suppliers.
Changes / Problems
We did not have major problems during this period.
Training & Professional Development
My program participated in 2 In-Service Training programs providing in formation needed by growers for managing water and fertilizers for optmizing tree health.
Dissemination Streams
We disseminated the results through journalpublications, conference proceedings, citrus industry magazine articles, and workshops. I also disseminated the results at professional society meetings including the SSS/ASA/CSSA (San Diego CA, and San Antonio, TX), FSHS(Orlando, FL) and ASHS (Las Vegas, NE). I and my students also shared results at the Southern Region Water Conference in College Station, TX.
Next Reporting Steps
I plan to publish 6 to 10 papers, participate at national societymeetings and grower workshops. <br><br>
<br>What was accomplished under these goals? We published 2 book chapters and 4 journals articles. We also delivered talks to growers at the Florida Citrus Show, Citrus Expo, Citrus Youth Day, Citrus Tree and Root Health, Citrus SoilHealth Forum,and other In-Service Trainings to extension agents. We conducted 6 major in-field experiments and 4 greenhouse studies related to irrigation, water quality and optimal fertilization. <br><br><b>Publications</b><br>
Target Audience
Objective 1. Develop and implement sustainable strategies that optimize water management for citrus production, conservation of water, maximization of tree productivity and minimization of water quality degradation; This objective was implemented in young and mature citrus trees in greenhouse and field conditions. We evaluated three N fertilizer rates including: IFAS recommendation for bearing and nonbearing trees (Obreza and Morgan, 2008), 75% of IFAS recommendation and 125% of IFAS recommendation with P and K fixed with respect to N, and also three K rates as follows: IFAS recommendation for bearing nonbearing trees (Obreza and Morgan, 2008), 75% of IFAS recommendation and 125% of IFAS recommendation with P and N fixed with respect to K unddr greenhouse conditions. Two irrigation rates, 100% evapotranspiration (ET) and 75% ET were used and trees were irrigated daily. Soil samples were collected twice during the year to analyze for pH, electrical conductivity, extractable ammonium and nitrate-N, P and K. Soil samples were extracted with 2 M KCl (Hanlon et al., 1997) and ammonium-N and nitrate-N and analyzed using a flow analyzer (QuikChem 8500, Lachat Instruments) at 660 and 520 nm, respectively (Harbridge, 2007a, 2007b). Mehlich-3 extraction was used for the determination of P and K (Hanlon et al., 1997). All Mehlich-3 sample extracts were analyzed by inductively coupled plasmaatomic emission spectrometry (Munter et al., 1984). Electrical conductivity and soil pH were determined using standard methods (Hanlon et al. 1997). Leaf nutrient concentrations were determined quarterly (Obreza and Morgan, 2008). Tissue N concentration (%) was determined using the NA2500 carbon (C)/N Analyzer (Thermoquest CE Instruments; ThermoQuest Corporation, Thermo Fisher Scientific Inc., Waltham, MA, USA) and compared with critical N levels for Florida Citrus (Obreza and Morgan, 2008; Obreza et al., 1999; Kadyampakeni et al., 2016). Tissue P and K concentration was determined using the dry ash combustion digestion method (Anderson and Henderson, 1988). The data collected was subjected to multivariate statistical analyses using SAS to establish effects of fertilization and irrigation rates on water quality, soil nutrient content and nutrient uptake of citrus trees. From this work, 2 conference proceeding papers were published in Florida State Horticultural Society at 2-3 additional manuscripts are in review for publication in refereed journals. For field studies, citrus fruit yields per tree are being estimated annually to determine the effect of fertilization and irrigation treatments. Water samples will be collected bi-weekly using suction lysimeters for nitrate, orthophosphate and pH analysis in summer months. Water samples from the plots will be collected using suction lysimeters at 6, 12, 18, and 30-inch depths to estimate nutrient retention capacity and leaching of fertilizer applied as a result of fertilization and irrigation methods (Soil moisture Corp., Pullman, WA). The water samples will be analyzed for nitrate using flow injection analysis systems (Harbridge, 2007a), and for orthophosphate P with colorimetry, while pH will be determined using standard methods (Hanlon et al. 1997). Soil moisture will be monitored continuously using soil moisture sensors commercially available in the US such as HS-10 from Decagon Inc, Pullman, WA at 6, 12, 18, and 30-inch depths. Tree water use will be evaluated using the non-destructive sap flow Dynagage technique (Dynamax Inc., Houston, Texas) (Kadyampakeni et al. 2014b). Leaching fluxes, estimated from soil moisture contents and hydraulic conductivity using Darcy's equation, will be estimated to establish the relations between irrigation rates and soil moisture content and tree performance. Leaf area will be determined using a portable leaf area meter (Model LI-3000A LI-COR, Lincoln, NB). Leaf area index (LAI) of each tree for each plot will be measured using a SunScan canopy analysis system (Dynamax Inc., Houston, TX) during a sunny day. In this goal, we are also developing programs for peach and blueberry irrigation for optimizing water and nutrient use efficiency on sandy soils. Results from these efforts will also be published in refereed journals. Objective 2. Develop local and regional water use models taking into consideration citrus planting systems, tree water requirements, irrigation scenarios, and water use for cold protection. Accurate estimation of water use would help in managing water demands in meeting citrus water requirements using alternative irrigation systems and irrigation scheduling options (Kadyampakeni et al. 2014a). Data are being collected for calibration and development of water use models for irrigation decision support. Existing models that will be used for piloting water use studies include HYDRUS2D, Root Zone Water Quality Model II (RZWQM2), and Citrus Water Management System (CWMS). We will continue expanding modeling scenarios for decision support and environmental sustainability. Objective 3. Apply precision agricultural technologies for local and regional water management. Precision agricultural technologies help growers to optimize resource use efficiency in citrus production using GIS techniques spatial analysis. The goal will explore optimal combination of water and nutrients using micro-irrigation and intensive fertigation systems based on site-specific tree requirements (Schumann et al. 2009). This will use variable rate fertilizer management through grid or zone sampling to determine the variability of the farmland soil fertility and fertilizers at variable rates will be applied onto each of those grids or zones (Zaman et al. 2005). Similarly soil moisture-based irrigation schedules would be developed according to the soil hydraulic properties of each zone and tree size. Thus, field performance per unit area could be mapped, tracked and analyzed for growers to know how poorly or well each zone is producing citrus. Analytical procedures for nutrients will be the same as described above while soil moisture (Decagon Inc., Pulman, WA) and plant sensors (Dynamax, Houston, TX) and weather stations (Davis Instruments, Hayward, CA) will be deployed to evaluate irrigation system performance and crop water use. Objective 4. Develop best management practices for water conservation and quality maintenance for surface and groundwater sources. Implementation of best management practices for water conservation and quality of water resources will result in improved water use and environmental quality in Florida citrus groves. This is achieved through water quality monitoring as explained in Objective 1 and also recording water volumes applied to citrus plantings. Further, intensive, frequent irrigation practices coupled with fertigation using microsprinkler and drip irrigation systems, and advanced irrigation management including regulated deficit irrigation (RDI) and/or alternate partial root zone drying (APRD) will be evaluated to determine the potential water savings and nutrient use efficiency, assess production costs and tree productivity in citrus infected with citrus greening. Data to collected include fruit yields, production costs and quantity of water used. We will document these impact in due course.
Changes / Problems
Nothing Reported
Training & Professional Development
I provided professional training to certified crop advisors and growers through a total of 5 talks in 2018 on improved water and nutrient management.
Dissemination Streams
We disseminated the results through publications in the Citrus Production Guide and also the Citrus Industry Magazine.
Next Reporting Steps
We plan to publish 4 to 6 journal articles, present some results at grower talks, continue data collection in field experiments, and recruit graduate students to help accomplsih the goals of the project. <br><br>
<br>What was accomplished under these goals? We published about 3 journal articles and one conferenc proceeding in 2018. <br><br><b>Publications</b><br>
Target Audience
Current focus of my research program is on optimal irrigation and nutrient application rates for citrus affected with Huanglongbing (HLB, aka citrus greening). The findings from the current investigations are packaged for wider grower audiences for adoption in their day-to-day practices due to lack of guidelines on water and nutrient management of HLB affected trees in the state. In 2017, I had given 3 grower talks, visited 9 groves affected by HLB and held 2 field tours for nine growers and 100 students from more than 20 states interested in remedial citrus water and nutrient management strategies.I pubished 9 journalpapers to share with the scientific community. In summary my target audience includes the industry, graduate students, fellow scientists and commercial citrus growers. A summary of myoutreach accomplishments is shown below. Summary of Relevant Extension Accomplishments Number/amount Refereed journal articles related to extension program 9 Creative works 2 Extension publications in EDIS 5 Extension articles in technical and trade magazines 1 Samples analyzed for pH or nutrient content 857 Presentations 5 Students in Agronomy Soils and Environmental Sciences Field Tour (participants) 100 Farmer Field Tour during CREC 100th Anniversary (participants) 9 In-service training for Certified Crop Advisors 1 Participants in CCA and Grower Workshops 383 CEUs Awarded during joint workshops 25
Changes / Problems
The project has been a success. However, someanalyses are still being done in commercial labs.I am planning to seek additional funding to buy more equipment for my program to be able to do water and soil quality analyses to minimize operational costs.
Training & Professional Development
The project provided knowledge on improved water and nutrient management to certified crop advisors (CCAs) and continuing edcuation units (CEUs) at 3 sessions in 2017. Some growers have already started implementing recommednations fro our studies.
Dissemination Streams
We have communicated results through presentation to growers at the Best Management Practice Workshop Fort Pierce, Citrus Institute, Lake Alfred and Citrus Expo,Fort Myers in Florida. The other results were disseminated to fellowscientists at the American Society of Horticultural Science meeting in Kona, Hawaii (Sept. 2017), Soil Science Society of America Annual Meetings in Tampa, FL (October 2017), Florida State Horticultural Society in Tampa, FL (FSHS, June 2017), and Irrigation Association in Orlando FL(December 2017).
Next Reporting Steps
Research activities I will continue working on 4 grant-funded projects 1) Improving performance of HLB infected trees and root health under partial root zone drying, 2) Reduction of Water Use for Citrus Cold Protection, 3) Integrated Plant Nutrition and Crop Protection Chemical Research to Mitigate HLB and other Citrus Diseases, and 4) Citrus Nutrient Management on Huanglongbing Affected Round Orange and Grapefruit Groves on Flatwoods and Ridge soils. This first project, funded under the UF/IFAS Citrus Initiative, seeks to a) investigate the optimum fertilization rate of HLB affected trees; b) determine canopy development, root density and water use under partial root zone drying in hydroponic systems; and c) compare the performance of biochar and compost in ameliorating soil functions and restoring soil microbial diversity. The project will lead to a refereed conference proceeding paper published in the Florida State Horticulture Society by June 2018 and 2 peer-reviewed journal articles submitted by May and December 2018. The second project funded by the Southwest Florida Water Management District will result in collation of data on Florida Automated Weather Network (FAWN) website and help growers with information related to freeze protection and cold acclimation in trees during winter months and explore ways of saving water. The third project seeks to address the citrus greening disease through integrated nutrition and crop protection packages in 4-year-old orange trees. It is being supported by YARA and BAYER CropScience. The fourth project, supported with UF/IFAS Citrus Initiative is being implemented at three sites in southwest and southeast flatwoods and central ridge, to 1) determine N requirement of HLB affected trees on flatwoods and ridge soils, 2) determine tree Ca, Mg, Mn, Zn, and B requirement of HLB affected trees by soil application, 3) compare foliar and ground applied micronutrient (Mn, Zn, and B), and 4) determine the influence of N nutrition on secondary macro- and micronutrient applications. The first, third and fourth projects will lead to novel guidelines on managing nutrition of HLB affected trees and a 3rd edition of 'Citrus Nutrition Guide'. I plan to participate in 4 professional conferences at Florida State Horticultural Society (June 10 to June 12, 2018 in Ft. Lauderdale, FL), the American Society of Horticultural Science Conference July 31 to Aug. 3, 2018, Washington, D.C., 21st World Congress of Soil Science (Aug. 12-17, 2018, Rio de Janeiro, Brazil), and the Irrigation Association Show (Dec. 3-7, 2018 in Long Beach, California). Seeking grant funding will remain a critical area of my program. I have put forward five grant proposals entitled 1) Improving citrus productivity using water- and nutrient-saving irrigation systems and effective psyllid management strategies ($290,044 to FDCAS); 2) Irrigation Management Innovations to Reduce Water Use, Improve Water Quality and Enhance Crop Yields ($4,693,454 to National Institute of Food and Agriculture (NIFA)), 3) Precision nutrient and irrigation management innovations for high peach yield and yield quality ($2,787,886 to NIFA), 4) Comprehensive evaluation of enhanced nutrition program effects on citrus plant growth, fruit yield and HLB bacterial titers ($1,361,748 to NIFA) and 5) A Southern Regional Water Conference to Improve Producer Adoption of Sustainable Water Management Practices ($50,000 to Sustainable Agriculture Research and Education (SARE)). I plan to publish two conference abstracts/papers, one book chapter and at least four journal articles in 2018. <br><br>
<br>What was accomplished under these goals? The following accompishments were made: Goal 1. This goal is being implemented in a greenhouse, UF/IFAS groves and selected grower cooperators. We are evaluating different rates of irrigation, nitrogen, selected macronutrients (Ca and Mg), and micronutrients such as B, Zn and Mn using precision irrigation and fertilization practices. To execute this goal, I got fundedby UF/IFAS Citrus Initiative and the Citrus Industry.Tosupport this goal, I have procured a Flow Injection analyzer (QuikChem 8500, Lachat Instruments) for ammonium-N and nitrate-N analysis in my lab and will use commercial labs for further nutrient analysis. On this objective, one conference proceeding article was published and a grower presentation was made. While one greenhouse experiment was completed, the field measurements of the selected parameters will continue for the next 3 to 4 years to craft new recommendation for improved water quality and nutrient management. Goal 2.We use soil moisture, sapflow and trunk sensors to estimate water use for trees. These sensors are automated and are accurate ways for measuring water use. My current focus is to assess the effect of regulated deficit irrigation strategies with full irrigation on citrus and other crops such as peach. My program is now developing a way of coupling canopy appearance and soil moisture data to determine water stress thresholds. We are also using process-oriented models e.g. HYDRUS 2D to determine water use in citrus. Goal 3. In this goal, my program is conducting a 3-year study on reduction of water use for freeze protection in 4 commercial groves of central Florida. The data generated will be used by growers to save water used for managing freezes in winter months. The data are made available to growers through Citrus industry articles and EDIS publications. My program is also trying to use process oriented models to estimate water use to manage water demands for meeting citrus water requirements using alternative irrigation systems and irrigation scheduling options. Data are being collected for calibration and development of water use models for irrigation decision support. Existing models for piloting water use studies include HYDRUS2D, Root Zone Water Quality Model II (RZWQM2), and Citrus Water Management System (CWMS). Goal 4. In this goal, implementation of best management practices for water conservation and quality of water resources will result in improved water use and environmental quality in Florida citrus groves. This is being achieved through water quality monitoring and also recording water volumes applied to citrus plantings. We have instruments for measuring pH, electrical conductivity and water quantities for irrigation. We are assessing intensive, frequent irrigation practices coupled with fertigation using microsprinkler and drip irrigation systems, and advanced irrigation management including regulated deficit irrigation (RDI) and/or alternate partial root zone drying (APRD) to determine the potential water savings and nutrient use efficiency and tree productivity in citrus affected with citrus greening. Most of the outputs are being published in EDIS and Trade journals and shared with growers and the citrus industry. <br><br><b>Publications</b><br>