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The postharvest loss in quality of grapefruit during storage can be quantified by determining the change of the quality traits of grapefruit, including total soluble solids (TSS), titratable acidity (TA), TSS/TA, weight loss (WL), and the development of decay (DC) and chilling injury (CI). The objective of this study was, therefore, to develop models that encompass the relationship between both storage conditions and duration and the quality traits of grapefruit to predict the loss of grapefruit quality during storage. The models of TSS, TA and TSS/TA were developed with experimental data collected during the 2007–08 and 2008-09 growing seasons that were obtained from the literature. The models for WL, DC, and CI were developed with experimental data collected in Florida during the 2004–05 and 2005-06 growing seasons. The WL, DC and CI models were applied to determine storage life. The results indicated that there was a second-order polynomial relationship between storage duration and TSS and linear relationships between storage duration and TA and TSS/TA. A longer storage duration resulted in a higher TSS, a lower TA and a higher TSS/TA. There were linear relationships between storage duration and WL, thermal time above a threshold temperature of 0 °C and DC and thermal time below 10 °C and CI, with higher WL, DC and CI resulting from longer storage duration and larger number of thermal times. Model performance for simulating TSS, TA, TSS/TA for storage temperature between 2 °C and 11 °C was good. There is good performance for simulating WL for storage temperature between 4 °C and 12 °C, DC for storage temperature of 21.1 °C, and CI for storage temperature of 4.4 °C. Following model development, it was applied to determine the optimum storage life. Optimum storage condition was a storage temperature of 7.6 °C for approximately 20 d, resulting in less than 5 % of the stored fruits lost due to unacceptable quality based on predictions for WL, DC and CI.

Since the first occurrence of Huanglongbing (HLB) in the Florida commercial citrus industry in 2004, fruit yield and yield components of HLB-affected citrus have declined in endemically affected citrus tree groves. Optimal fertilization is thus critical for improving tree performance because nutrients are vital for tree growth and development, and play a significant role in tree disease resistance against various biotic and abiotic stresses. The objective of the current study was to determine whether leaf nutrient concentration, tree growth, yield, and postharvest quality of HLB-affected citrus trees were improved by the split application of nutrients. The four micronutrient application rates were used as fixed factors and the three nitrogen (N) rates were used as random factors for leaf nutrient analyses, tree growth, fruit yield, and postharvest analyses. Significant leaf manganese (Mn) and zinc (Zn) concentrations were detected when trees received foliar and soil-applied micronutrients regardless of the N rates. There was a strong regression analysis of leaf Mn and Zn nutrient concentration and nutrient rates with R2: 0.61 and 0.59, respectively. As a result, a significant leaf area index associated with foliar and soil-applied micronutrient rates had a positive correlation with leaf area index and soil pH with R2: 0.58 and 0.63 during the spring and summer seasons, respectively. Trees that received a moderate (224 kg·ha−1) N rate showed the least fruit decay percentage and total soluble solids (TSS) of 8% more than the lowest (168 kg·ha−1) and highest (280 kg·ha−1) N rates, even though fruit yield variations were barely detected as these micronutrients promoted vegetative growth. Moreover, the TSS to titratable acidity (TA) ratio of foliar and soil-applied micronutrient-treated trees showed 2% and 7% greater values than the foliar-only treated and control trees, respectively. Although micronutrients exacerbated stem-end rind breakdown (SERB), these nutrients significantly improved fruit storage when the fruits were stored for extended periods (8–11 weeks). Thus, moderate N rate, foliar (1×), and soil-applied (1×) micronutrient treatments improved tree growth, fruit postharvest, and fruit storage characteristics.

Citrus Black Spot (CBS) causes considerable damage to the Florida citrus industry. Early detection of CBS, especially in the presence of other peel blemishes, would enable better mapping and control of CBS spread, reduce wasted fruit, and permit early removal of culls from the packing stream. Oranges whose peels bore the symptoms of four defects/disease (CBS, greasy spot, melanose, and wind scar), as well as a normal control group, were imaged with a hyperspectral imaging system. Principal Component Analysis- (PCA) and Linear Discriminant Analysis (LDA) -based methods were employed to select bands from these images, and a custom convolutional neural network (CNN) for feature extraction was trained with these bands. The extracted features permitted classification of the peel conditions with four classifiers: SoftMax, Support Vector Machines (SVM), Random Forest Classifier (RFC), and K-Nearest Neighbors (KNN). A mean overall accuracy of 94.9 % was achieved using an SVM classifier on five bands selected with PCA, and 90.2 % with LDA-selected bands. These results show the potential of CNNs to extract features for automated postharvest citrus inspection.

Grapefruit are well-adapted to arid and warm climatic conditions, but well-irrigated trees usually produce better-quality fruits. Because water is a major component of the fruits, there is a strong relationship between drought stress and fruits quality traits such as fruits size, external fruits color, and juice quality. The object of this study was to develop a computer model to predict postharvest external grapefruit color as a function of drought stress. During model development, drought stress was quantified using a concise water balance model based on crop evapotranspiration, precipitation, and irrigation. Data collected from Murcia, Spain, during the 2007 and 2008 growing seasons were used for model development, and the model was optimized by comparing model predictions and observations for each growing season. The root mean square error and Nash and Sutcliffe coefficient of efficiency (NSE) were used to evaluate model performance. Then, the model was evaluated with independent data collected from Florida during the 2005–06 growing season. A second-order polynomial relationship was found between external fruits color and drought stress, with less drought stress resulting in better external fruits color. Model optimization revealed good model performance for predicting external fruits color in Murcia, with NSE values of 0.975 and 0.979 for the 2007 and 2008 growing seasons, respectively. Model evaluation with the data from Florida showed that model predictions were reliable, with a NSE value of 0.984. A robust model to predict external grapefruit color as affected by drought stress was developed during the present study and could be potentially applied to supply information for suitable irrigation management of various grapefruit cultivars grown under different climatic conditions. Model performance could be confirmed by future research with data collection during further multiple seasons for different cultivars and a range of climatic conditions.

Stonefruit grown commercially in Florida include peaches, nectarines, and plums. This publication is directed to current and potential stonefruit growers, handlers, and marketers, as well as researchers, extension agents, students, and consumers. It provides information about the Florida stonefruit industry, stonefruit cultivars that are suitable for Florida, stonefruit postharvest physiology and pathology, fruit quality, and recommended postharvest handling and marketing practices.

Identification and segregation of citrus fruit with diseases and peel blemishes are required to preserve market value. Previously developed machine vision approaches could only distinguish cankerous from non-cankerous citrus, while this research focused on detecting eight different peel conditions on citrus fruit using hyperspectral (HSI) imagery and an AI-based classification algorithm. The objectives of this paper were: (i) selecting the five most discriminating bands among 92 using PCA, (ii) training and testing a custom convolution neural network (CNN) model for classification with the selected bands, and (iii) comparing the CNN’s performance using 5 PCA bands compared to five randomly selected bands. A hyperspectral imaging system from earlier work was used to acquire reflectance images in the spectral region from 450 to 930 nm (92 spectral bands). Ruby Red grapefruits with normal, cankerous, and 5 other common peel diseases including greasy spot, insect damage, melanose, scab, and wind scar were tested. A novel CNN based on the VGG-16 architecture was developed for feature extraction, and SoftMax for classification. The PCA-based bands were found to be 666.15, 697.54, 702.77, 849.24 and 917.25 nm, which resulted in an average accuracy, sensitivity, and specificity of 99.84%, 99.84% and 99.98% respectively. However, 10 trials of five randomly selected bands resulted in only a slightly lower performance, with accuracy, sensitivity, and specificity of 98.87%, 98.43% and 99.88%, respectively. These results demonstrate that an AI-based algorithm can successfully classify eight different peel conditions. The findings reported herein can be used as a precursor to develop a machine vision-based, real-time peel condition classification system for citrus processing.

The spatial arrangement and growth pattern of root systems, defined by the root system architecture (RSA), influences plant productivity and adaptation to soil environments, playing an important role in sustainable horticulture. Florida’s peach production area covers contrasting soil types, making it necessary to identify rootstocks that exhibit soil-type-specific advantageous root traits. In this sense, the wide genetic diversity of the Prunus genus allows the breeding of rootstock genotypes with contrasting root traits. The evaluation of root traits expressed in young seedlings and plantlets facilitates the early selection of desirable phenotypes in rootstock breeding. Plantlets from three peach × (peach × almond) backcross populations were vegetatively propagated and grown in rhizoboxes. These backcross populations were identified as BC1251, BC1256, and BC1260 and studied in a completely randomized design. Scanned images of the entire root systems of the plantlets were analyzed for total root length distribution by diameter classes, root dry weight by depth horizons, root morphological components, structural root parameters, and root spreading angles. The BC1260 progeny presented a shallower root system and lower root growth. Backcross BC1251 progeny exhibited a more vigorous and deeper root system at narrower root angles, potentially allowing it to explore and exploit water and nutrients in deep sandy entisols from the Florida central ridge.

The prevalence of Huanglongbing (HLB) in Florida has forced growers to search for new management strategies to optimize fruit yield in young orchards and enable earlier economic returns given the likelihood of HLB-induced yield reductions during later years. There has been considerable interest in modifying orchard architecture design and fertilizer and irrigation management practices as strategies for increasing profitability. Our objectives were to evaluate how different combinations of horticultural practices including tree density, fertilization methods, and irrigation systems affect growth, foliar nutrient content, fruit yield, and fruit quality of young ‘Valencia’ sweet orange [Citrus sinensis (L.) Osbeck] trees during the early years of production under HLB-endemic conditions. The study was conducted in Fort Pierce, FL, from 2014 to 2020 on a 1- to 7-year-old orchard and evaluated the following treatments: standard tree density (358 trees/ha) and controlled-release fertilizer with microsprinkler irrigation (STD_dry_MS), high tree density (955 trees/ha) with fertigation and microsprinkler irrigation (HDS_fert_MS), and high tree density with fertigation and double-line drip irrigation (HDS_fert_DD). Annual foliar nutrient concentrations were usually within or higher than the recommended ranges throughout the study, with a tendency for decreases in several nutrients over time regardless of treatment, suggesting all fertilization strategies adequately met the tree nutrient demand. During fruit-bearing years, canopy volume, on a per-tree basis, was higher under STD_dry_MS (6.2–7.2 m3) than HDS_fert_MS (4.3–5.3 m3) or HDS_fert_DD (4.9–5.9 m3); however, high tree density resulted in greater canopy volume on an area basis, which explained the 86% to 300% increase in fruit yield per ha that resulted in moving from standard to high tree density. Although fruit yields per ha were generally greatest under HDS_fert_MS and HDS_fert_DD, they were lower than the 10-year Florida state average (26.5 Mg·ha−1) for standard tree density orchards, possibly due to the HLB incidence and the rootstock chosen. Although tree growth parameters and foliar nutrient concentrations varied in response to treatments, management practices that included high tree density and fertigation irrespective of irrigation systems produced the highest fruit yields and highest yield of solids. Soluble solids content (SSC) and titratable acidity (TA) were lower, and the SSC-to-TA ratio was highest under STD_dry_MS in 2016–17, with no treatment effects on quality parameters detected in other years. Both drip and microsprinkler fertigation methods sufficiently met tree nutrient demand at high tree density, but additional research is needed to determine optimal fertilization rates and better rootstock cultivars in young high-density sweet orange orchards under HLB-endemic conditions in the Indian River Citrus District.

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Citrus greening (huanglongbing, HLB) is a bacterial disease caused by Candidatus Liberibacter asiaticus (CLas) and vectored by the Asian citrus psyllid (Diaphorina citri) (ACP). No cure is yet available, and as a result, increased fertilizer applications continue to be a major management method used to prolong the productive life of affected trees. However, questions remain regarding proper fertilizer rates and in what form these nutrients should be applied to increase tree health and yield. Therefore, the goal of this study was to identify optimum micronutrient application forms and rates to increase root growth, canopy size and fruit yield as well as reduce leaf and root CLas cycle threshold (Ct) value of HLB-affected grapefruit trees (Citrus × paradisi Macfad). A large-scale field study consisting of six-year-old HLB-affected ‘Ruby Red’ grapefruit trees grafted on ‘sour orange’ (Citrus × aurantium) rootstock was conducted in the Florida Indian River District. Eight different treatments consisting of four granular and four liquid fertilizers with 1×, 2×, and 4× the current University of Florida, Institute of Food and Agricultural Sciences recommended rates of boron, zinc, manganese, and iron were applied for three times a year (granular), biweekly (liquid), or weekly (liquid), for three years. Root density, length and diameter, root, and leaf CLas Ct value, canopy volume, visual HLB symptoms, and fruit yield were measured throughout the study. Regardless of treatment, tree health declined over time, and no significant impact on severely HLB-affected grapefruit tree health was detected within the three-year time frame of the study. This was the first study to solely compare the impact of ground applied micronutrient application rates and methods on HLB-affected grapefruit tree health in Florida’s Indian River District. More time would be needed to determine the potential benefits of increased micronutrient performance of HLB-affected grapefruit trees.

Rootstocks are fundamental for peach production, and their architectural root traits determine their performance. Root-system architecture (RSA) analysis is one of the key factors involved in rootstock selection. However, there are few RSA studies on Prunus spp., mostly due to the tedious and time-consuming labor of measuring below-ground roots. A root-phenotyping experiment was developed to analyze the RSA of seedlings from ‘Okinawa’ and ‘Guardian’™ peach rootstocks. The seedlings were established in rhizoboxes and their root systems scanned and architecturally analyzed. The root-system depth:width ratio (D:W) throughout the experiment, as well as the root morphological parameters, the depth rooting parameters, and the root angular spread were estimated. The ‘Okinawa’ exhibited greater root morphological traits, as well as the other parameters, confirming the relevance of the spatial disposition and growth pattern of the root system.

The Southeastern United States is facing agriculture crises, such as the ongoing epidemic of citrus greening disease that has forced the region to begin looking into alternative crops. Some of these belong to the Rosaceae genus Prunus, which encompasses many economically important species such as peaches, almonds, cherries, plums, and more. Peach production in Florida has become a very promising alternative to citrus; however, there are different limitations and challenges that peach production faces in this region. Differing climates coupled with edaphic challenges such as salinity, alkalinity, and waterlogging have been the focus of much of the research into the viability of peach production in the region. Using the genetic diversity of the Prunus genus is crucial to the success of peach as an alternative crop, due to the nature of its propagation on rootstocks. The development of new rootstock cultivars has been—and continues to be—the most efficient way not only to deal with the variety of problems associated with the climate and soil mentioned above but also to mitigate the effects of pests and diseases. The vegetative propagation of stone fruit rootstocks also has distinct advantages that seed propagation cannot achieve, including tree performance uniformity and the multiplication of interspecific hybrids. Tools used to select the best-performing rootstocks for the area such as the root system architecture (RSA) analysis are fundamental to this development process to ensure that the rootstock cultivars with the traits needed for success in the region are selected. This narrative review lays out all the challenges facing southeastern peach production in detail, discussing the research into these challenges and highlighting the tools that are most crucial to the success of peach production in the region to create a resource for researchers, growers, and breeders to more easily access this information.

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This article informs about pre- and postharvest factors influencing citrus fruit peel color for fresh markets and the best postharvest treatment methods for obtaining excellent peel color. Peer reviewed through UF/IFAS Citrus Research and Education Center; published in Citrus Industry Magazine.

Citrus production under enclosed structures can exclude the Asian citrus psyllid (ACP, Diaphorina citri) and eliminate the negative effects of citrus greening or huanglongbing (HLB) disease caused by Candidatus Liberibacter asiaticus to the grapefruit (Citrus paradisi) fresh fruit industry. Physically impeding the insect vector from accessing trees is a logical method to have disease-free groves. Our objectives were to assess the ability of enclosed screenhouses to exclude the ACP, stop HLB inoculation and dissemination, and improve fruit yield of in-ground and container-grown 6-year-old “Ray Ruby” grapefruit at super-high planting densities relative to open-air trees. We built a large structure to allow commercial-scale trials and tested two production systems (screenhouse and open-air), two planting systems (in-ground and potted), and two rootstocks (“Sour Orange” [Citrus × aurantium] and “US-897” [Citrus reticulata × Poncirus trifoliate]). The experimental design was a randomized complete block design split-split-plot with four replications. Four passively ventilated 1,080-m2 completely enclosed screenhouses were constructed using a 50-mesh monofilament high-density polyethylene screen. The main support for each enclosed, covered structure consisted of pressure-treated, wooden utility poles. Trees were planted in Sept/2013 on a density of 1,957 trees/ha. Irrigation was performed on-demand using two 7.6-LPH drip emitters per tree, and fertigation was applied three times/week using 15N-2.6P-22.4K water-soluble fertilizer at 180 kg N/ha. Psyllids were monitored using sticky cards and detected inside the screenhouses post-Hurricane Irma, which damaged the screen structures in Sept/2017, leaving openings until repairs were completed in Apr/2018. Screen aging and a tropical storm in April/2019 caused another major screen opening fixed in Oct/2019. Despite the weather-related damages to the screens, only trees cultivated in open-air tested positive for Candidatus Liberibacter asiaticus after 6 years. There was fast disease progression for all outside treatments, with 100% infection. Covered, in-ground trees exhibited the highest trunk diameter and canopy volume (P < 0.0001). Trees grown inside screenhouses exhibited higher fruit yield than outside trees, with the highest yield observed for in-ground trees on “US-897” (51,081 kg/ha) (P < 0.0001). Several open-air treatments particularly in containers did not produce any fruit. On the other hand, potted grapefruit trees cultivated inside the enclosures had the highest soluble solids content (P < 0.001). The screenhouses provided disease exclusion, increased fruit yield, and fruit quality, representing an alternative for growers interested in producing high-quality fruit for the fresh market. Production cost and economic viability still need to be evaluated for large-scale implementation.

Citrus fruit decay is one of the most important constraints that affect fresh citrus quality and marketing values. It is most often caused by fungal or oomycete pathogens that grow and develop in the hot and wet conditions typical of Florida. This fact sheet is part of the 2019–2020 Florida Citrus Production Guide. Written by Mark A. Ritenour, Jiuxu “John” Zhang, Liliana M. Cano, and Megan M. Dewdney, and published by the Horticultural Sciences Department, March 2019. CIR359A/CH081: 2022–2023 Florida Citrus Production Guide: Decay Control of Florida Fresh Citrus (ufl.edu)

This 8-page fact sheet is part of the 2019–2020 Florida Citrus Production Guide. The objective of this document is to present general GAPs principles and PSR requirements needed to plan, execute, and document production practices that will prevent, minimize, or eliminate the possibility of fruit contamination. The materials contained in this document are a combination of recommendations based on the best available science and minimum standards outlined in the PSR. The distinction between voluntary GAPs recommendations and PSR requirements is made in this document by the deliberate use of the words “must” and “should” where “must” is used to denote PSR requirements and “should” is used to denote voluntary GAPs. This document will be reviewed and updated as new risk data emerges and as the Produce Safety Rule guidance is released from FDA; this is not a comprehensive list of all PSR requirements. Written by Travis K. Chapin, Michelle D. Danyluk, Renee M. Goodrich-Schneider, Keith R. Schneider, Matt Krug, Mark A. Ritenour, and Tripti Vashisth, and publsihed by the Agronomy Department, March 2019. CPG09/CG090: 2022–2023 Florida Citrus Production Guide: Food Safety Requirements and Considerations for the Florida Citrus Grower (ufl.edu)

This 5-page fact sheet is part of the 2019–2020 Florida Citrus Production Guide. Written by Mark A. Ritenour and published by the Horticultural Sciences Department, March 2019. HS1301/HS1301: 2022–2023 Florida Citrus Production Guide: Fresh Fruit Pesticide Residue Limits (ufl.edu)

This chapter focuses on methods and techniques for reducing losses in postharvest quality during typical commercial handling operations. This document is HS719, Horticultural Sciences Department, UF/IFAS Extension. Published November 2006.

Traditionally, peach rootstocks are propagated by seeds due to their high availability, low cost, and easy storage and handling. However, stem cuttings allow the propagation of interspecific hybrids and keep the genetic uniformity of heterozygous genotypes. This study compared the effect of four different concentrations of K-IBA (indole-3-butyric acid potassium salt) on softwood cuttings of three peach backcrosses (peach × (peach × almond)) for rootstock propagation in two propagation systems: aeroponics and germination trays. The four concentrations of K-IBA applied were: 0.0% (w/v) as a control, 0.1% (w/v), 0.2% (w/v), and 0.4% (w/v). Data were collected on the survival rate (%), rooting rate (%), and root growth parameters. The relevance of auxin for peach cuttings rooting was evidenced. K-IBA at 0.2% showed the best rooting effect for peach softwood cuttings, evidenced by its high rooting rate and higher survival rate. K-IBA at 0.4% and 0.2% produced the highest number of adventitious roots. The highest root growth parameters were obtained in germination trays, confirming the suitability of this system for root growth. However, aeroponics was demonstrated to be as efficient as the traditional germination trays for the rooting of peach cuttings, allowing for a more controlled environment with a better use of resources.

Conventionally managed citrus orchards can be modified to incorporate advanced horticultural practices such as higher plant density and efficient water and fertilizer application known as open hydroponics system (OHS) to increase productivity under Huanglongbing (HLB) endemic conditions. A field study was conducted from 2013 to 2018 to evaluate the effect of an OHS on “Ray Ruby” grapefruit (RR) production under HLB-endemic conditions. We tested a combination of different rootstocks [Sour orange (RR/SO) and US-897 (RR/897)], tree planting densities [standard (STD, 358 trees per ha) and high density staggered (HDS, 953 trees per ha)], fertilization methods (dry granular—dry and fertigation—fert), and irrigation systems (double driplines—DD and microsprinkler—MS), arranged in five treatments: RR/SO_STD_dry_MS, RR/SO_HDS_fert_DD, RR/897_HDS_fert_MS, RR/897_HDS_fert_DD, and RR/SO_HDS_fert_MS. All trees were infected by Candidatus Liberibacter asiaticus five years after planting. Trunk diameter and canopy volume increased over time and were higher under RR/SO_STD_dry_MS compared to other treatments. Total fruit number increased in 2016/17 compared to other seasons; however, 65% of fruit were classified as small (

This identification sheet was designed to assist packinghouse employees to identify the early yet subtle symptoms of citrus black spot. Proper identification of citrus black spot prevents the rejection of international fruit shipments. Esta identificación de hoja fue diseñada para ayudar a los empleados de las compañías de empaque a identificar rápidamente los síntomas sútiles de la mancha negra de los cítricos. La correcta identificación de la mancha negra de los cítricos previene el rechazo de los envois de fruta internacionales. This 1-page fact sheet is a minor revision written by M. M. Dewdney, J. D. Burrow, and M. A. Ritenour, and published by the Plant Pathology Department, August 2018. PP285/PP285: Identification of Early Citrus Black Spot Symptoms (Identificacíon de los Síntomas Iniciales de la Mancha Negra de los Cítricos) (ufl.edu)

Current citrus production practices often include the use of various chemicals, many of which are pesticides. Chemical residues on the fruit after harvest are a concern to regulators and the public alike because of their potential negative health effects. Therefore, the US and other countries set maximum residue limits (MRLs) on fresh produce for various chemicals. This 5-page document is part of the 2017-2018 Florida Citrus Production Guide and discusses the MRLs for various chemicals used on Florida citrus. Written by Mark Ritenour and published by UF’s Horticultural Sciences Department, July 2017. HS1301/HS1301: 2022–2023 Florida Citrus Production Guide: Fresh Fruit Pesticide Residue Limits (ufl.edu)

This is a quick identification tool of citrus blemishes and fruit decay caused by fungi and bacteria in Florida citrus. Original publication date May 2017.

This poster is an identification tool for common disorders and injuries in Florida citrus.

The Food Safety Modernization Act that President Obama signed into law January 4, 2011 represents the most sweeping update to food safety regulation since the Federal Food, Drug, and Cosmetic Act of 1938. As part of FSMA, registration is required of facilities that manufacture, process, pack or hold food for human or animal consumption. This 3-page fact sheet was written by Susanna Richardson, Renée Goodrich Schneider, Mark A. Ritenour, Michelle D. Danyluk, and Keith R. Schneider, and published by the UF Department of Food Science and Human Nutrition, July 2013. http://edis.ifas.ufl.edu/fs231

Growers are the first step in the farm-to-table food chain. Good Agricultural Practices (GAPs) refer to practices growers follow to prevent, minimize, or eliminate contamination and hazards to human health. Essential components of the GAPs process include careful planning, implementation, and documentation of required steps and procedures that together analyze and minimize risks imposed by biological, chemical, and physical hazards. The general guidelines presented in this document were developed by UF/IFAS for Florida citrus growers, in partnership with the citrus industry. This 8-page fact sheet was written by Michelle D. Danyluk, Renée M. Goodrich-Schneider, Keith R. Schneider, Mark A. Ritenour, and Timothy M. Spann, and published by the UF Department of Food Science and Human Nutrition, February 2012.

This bilingual identification sheet was designed to assist packinghouse employees to identify the early yet subtle symptoms of citrus black spot. Proper identification of citrus black spot prevents the rejection of international fruit shipments. Written by M. M. Dewdney, J. D. Yates, and M. A. Ritenour and published by the UF Department of Plant Pathology, July 2011. PP285/PP285: Identification of Early Citrus Black Spot Symptoms (Identificacíon de los Síntomas Iniciales de la Mancha Negra de los Cítricos) (ufl.edu)

HS1165, a 7-page fact sheet by Timothy M. Spann, Ryan A. Atwood, Megan M. Dewdney, Robert C. Ebel, Reza Ehsani, Gary England, Stephen H. Futch, Tim Gaver, Tim Hurner, Chris Oswalt, Michael E. Rogers, Fritz M. Roka, Mark A. Ritenour, Mongi Zekri, Brian J. Boman, Kuang-Ren Chung, Michelle D. Danyluk, Renee Goodrich-Schneider, Kelly T. Morgan, Robert A. Morris, Ronald P. Muraro, Pamela Roberts, Robert E. Rouse, Arnold W. Schumann, Philip A. Stansly, and Lukasz L. Stelinski, provides guidance to the Florida citrus industry in making management decisions regarding huanglongbing (HLB, citrus greening). Published by the UF Department of Horticultural Sciences, June 2010.

HS-1082, a 5-page article by M.A. Ritenour, S.A. Sargent, J.A. Bartz, and E.E. Lon Kan, is the Spanish language version of HS-761, Chlorine Use in Produce Packing Lines. It outlines principles for effectively using chlorine for water sanitation including sections on forms of chlorine, factors influencing chlorine activity, how to maintain adequate chlorine concentrations, test kits, recommendations, and how to mix chlorine solutions. Published by the UF Department of Horticultural Sciences, February 2007. HS1082/HS336: Uso del Cloro en las Líneas de Empacado de Productos Cosechados Frescos (ufl.edu)

In 1990, Congress passed the Organic Foods Production Act, part of the 1990 Farm Bill, requiring the USDA to develop national standards for organically produced agricultural products. This was done to assure consumers that agricultural products marketed as organic meet consistent, uniform standards. After ten years of debate and discussion, the final rule of the National Organic Program (NOP) was published in the Federal Register in December, 2000 and fully implemented in October 21, 2002. This final rule codifies the National Organic Program and refers to specific regulations whereas the National Organic Program refers to the overall program established by the federal Organic Foods Production Act of 1990. This document is HS983, one of a series of the Horticultural Sciences Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Publication date: July 2004. https://edis.ifas.ufl.edu/hs211

Early varieties of citrus fruit in Florida usually meet legal maturity standards before the peel attains the characteristic varietal color and therefore require degreening. Occasionally, later maturing varieties may similarly require degreening. The degreening process, which involves the use of ethylene gas in specially constructed degreening rooms, destroys the chlorophyll and allows the yellow or orange peel to predominate. This document is Cir 1170, Horticultural Sciences Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Publication date: August 2003. Cir 1170/HS195: Recommendations for Degreening Florida Fresh Citrus Fruits (ufl.edu)

Irrigation and fertilization are important components of commercial citrus production. Irrigation is necessary to adequately replenish soil water lost through evaporation and transpiration. Fertilizers replace nutrients removed during harvest and through leaching. They also maintain tree growth and vigor. Optimum management of both is critical for obtaining maximum yield. Irrigation and fertilization practices can also have significant impacts on fruit quality and shelf life during harvest, packinghouse operations, storage, and distribution. These include effects on fruit color, texture, disease susceptibility, juice composition, and the development of physiological disorders. 1. This document is HS942, one of a series of the Horticultural Sciences Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Original publication date: July 2002. Revised publication date: August 2003. https://edis.ifas.ufl.edu/ch158

Sporadic reports of stem-end rind breakdown (SERB) on fresh citrus fruit occur each season in Florida. SERB is most severe on oranges and Temples, but it may also occur on tangelos and grapefruit. Although there is still much that needs to be learned about the development and prevention of SERB, there are some principles that can be applied to help reduce SERB development in fresh fruit packed in Florida. This document is HS936, one of a series of the Horticultural Sciences Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Publication date: July 2003. HS936/HS193: Stem-End Rind Breakdown of Citrus Fruit (ufl.edu)

Chilling injury (CI) is a physiological disorder that is occasionally reported on fresh citrus shipments from Florida. It is most often characterized by areas of the peel that collapse and darken to form pits. Pitting is not targeted to the oil glands. Less severe symptoms may show up as circular or arched areas of discoloration or scalding. Packers and shippers should keep in mind several factors that influence if and to what degree grapefruit develop CI. This document is HS935, one of a series of the Horticultural Sciences Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Publication date: July 2003. HS935/HS191: Chilling Injury of Grapefruit and its Control (ufl.edu)

Blossom-end clearing (BEC) is characterized by the translucent, watersoaked appearance of the fruit peel (most commonly at the blossom end) caused by internal bruising and juice leakage from juice vesicles. Juice vesicles in the bruised areas usually have a gray tinge compared with unbruised tissue, and BEC-affected fruit develop off flavors. BEC is visible within 24 hours after bruising (often much earlier) and can affect up to 90% of the fruit in some loads. Decay, in particular mold, often develops in areas with BEC symptoms. BEC has also been referred as “wet bottoms,” “stylar-end clearing,” “water bottom,” “waterlog,” and “wet wick.” This document is HS937, one of a series of the Horticultural Sciences Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Publication date: July 2003. HS937/HS194: Blossom-End Clearing of Grapefruit (ufl.edu)

This document is FSHN0212, one of a series of the Food Science and Human Nutrition Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Publication: October 2002. https://edis.ifas.ufl.edu/fs093

This document is HS-761, one of a series of the Horticultural Sciences Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Publication Date: November 2002. HS761/CH160: Chlorine Use In Produce Packing Lines (ufl.edu)