Progress 10/01/13 to 09/30/14
Outputs
Target Audience: The primary audiences for this information have been growers, harvesters, packers, and shippers of fresh citrus. Fellow researchers are also an audience to spur scientific discussion and the development of future experiments. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided? Conferences attended: MRL Harmonization Workshop, June 2014, San Francisco, CA. Florida State Horticultural Society Annual Meetings, June 2014, Orlando, FL. American Society for Horticultural Sciences annual meetings, July 2014, Orlando, FL How have the results been disseminated to communities of interest? Presentations: Postharvest Degreening and Ripening Practices and Technology. June-July 2014 (separate presentations at the following universities) China Agriculture University, Beijing, China Beijing Technology and Business University, Beijing, China Southwest University Chongqing, China Fujian Agriculture and Forestry University, Fuzhou, China Non-Anticipated Impacts of Residue Tolerances. 2014 MRL Harmonization Workshop, June 2014, San Francisco, CA. Field and Packing Facility Sanitation. Part of the workshop, "Developing & Implementing a Hazard Analysis, Risk-Based Preventive Control (HARPC) Safety Plan for Fresh Produce", February 2014, Athens, GA. Sanitation During Transportation. Part of the workshop, "Developing & Implementing a Hazard Analysis, Risk-Based Preventive Control (HARPC) Safety Plan for Fresh Produce", February 2014, Athens, GA. Temperature & Relative Humidity Conditions During Transport of Gift Fruit Citrus Shipments. Florida Gift Fruit Shippers Association Annual Meeting, Sept. 19, 2014, Melbourne, FL. Update on Fruit Quality Issues, Peel Breakdown, and Decay Control. Fifty-Third Annual Citrus Packinghouse Day, Aug. 21, 2014, Fort Pierce, FL. Preliminary Report on Temperature & Relative Humidity Conditions During Transport of Gift Fruit Citrus Shipments. Florida Gift Fruit Shippers Association Board Meeting, May 13, 2014, Orlando, FL. Pre- and Postharvest Practices to Maximize Quality and Minimize Postharvest Decay and Disorders of Fruits and Vegetables. New Technology for Commercial Vegetable and Fruit Production (II). February 2014, Gainesville, FL (& via Polycom throughout the state). Temperature and Relative Humidity Conditions During Transport of Commercial Gift Fruit Citrus Shipments. Florida State Horticultural Society Annual Meetings, June 2014, Orlando, FL. Agricultural Challenges and Issues for Martin County. Martin County Board of County Commissioners Public Meeting. Sept. 23, 2014, Stuart, FL. Grade lowering Defects on Fresh Fruit. Florida Citrus Show, January 2014, Ft. Pierce, FL. Correct Identification of Citrus Fruit Diseases. Presented to 3 different industry groups within the state. Principles of Good Food Safety/Hygiene. Presented to 12 different industry groups within the state. OSHA Standard Changes Resulting from the Globally Harmonized System. Presented to 4 different industry groups within the state. The presentations on correct identification of citrus disease was as part of team of UF/IFAS research and Extension faculty and was part of 12 workshops conducted during the current reporting period throughout different citrus growing regions of Florida, training approximately 1,089 workers from 33 different companies. In all, approximately 4000 laminated sheets, posters and other visual aids illustrating and contrasting symptoms of citrus canker and citrus black spot with various defects and diseases that are not of quarantine significance. These workshops have become an annual program and are an important contributor to preventing infected fruit from being shipped to restrictive export markets. Such markets have never reported finding citrus canker or black spot on fresh citrus from Florida. Often during the same training program, we also gave presentations on good food safety/hygiene and personal hygiene. During the current reporting period, more than 33 different companies/businesses participated, resulting in 1,327 documented and trained employees in Food Safety. What do you plan to do during the next reporting period to accomplish the goals? Evaluate and develop ways to control citrus black spot symptom development on harvest fruit. Research will continue evaluating in vitro effects of essential oils, heat, fungicides, and systemic acquired resistance inducing compounds, but will also combine treatments (e.g., heated fungicides) and will evaluate treatments on symptomatic and asymptomatic fruit from blocks with citrus black spot. In addition to potassium phosphite, I will expand work with heated fungicide solutions to control a broader range of postharvest decays in fresh Florida citrus. Postharvest evaluations of new fresh fruit selections will continue and factors that influence fruit peelability will be expanded to more varieties and how peelability changes during maturation.
Impacts
What was accomplished under these goals?
Postharvest Evaluations of Promising New Fresh Citrus Fruit Selections: A total of 15 different mandarin, orange, and grapefruit/pummelo hybrids were received and evaluated for the 2013-2014 season. Our breeder collaborators indicate that fruit numbers available for testing this season were reduced due to disease and fruit drop. This corresponds to the relatively low citrus yields experienced statewide. However, over the past few years, several selections have been moved through the early release program and so the number of available fruit for testing is anticipated to increase greatly over the next few years. Such fruit volumes are required to conduct the types of studies needed to determine optimum postharvest handling methods and conditions. Fruit evaluated before release have almost always been very few and suitable only for giving a very rough idea of potential market life and quality. Peelability - Beside testing peelability of the cultivars received, we also tested changes in peelability of 'Ruby' red and 'Marsh' grapefruit during long-term storage at 50F (10C) for up to 78 days. With fruit from these harvests, we also repeated experiments from last season evaluating the effect of fruit temperature on peelability. Fruit were harvested from commercial blocks and initial peelability measured in December. Measurements were also taken of each fruit's size, weight, and thickness of peel to evaluate for any correlation with peelability. Compared to 'Ruby' red grapefruit, 'Murcott' tangerine had a thinner peel, but maintained peel integrity better, and required less peak and mean force to remove the peel. Only fruit at the higher temperature (74F) maintained peel integrity better, and required greater peek and mean force to remove the peel compared to fruit at 40F or 50F. The effects of storage time on peelability was not as clear. Although peel integrity tended to decline over time in storage, peek and mean peeling force did not demonstrate a clear trend. In addition, no significant relationships could be found between fruit size, weight, peel thickness, and peelability. Methods to Screen Cultivars for Susceptibility to Postharvest Disorders - To evaluate if screening techniques could be developed to identify cultivars that may be susceptible to developing particular postharvest disorders, a collaborative effort was initiated with a visiting scientist with expertise in identifying genes expressed during the development of citrus granulation, a disorder that occasionally develops in fresh Florida citrus, especially late-season navel oranges. We successfully obtained pure and intact total RNAs extracted from granulated and non-granulated Washington navel orange juice sacs and successfully identified genes specifically induced in granulated tissue. A subtracted cDNA library was created and tested 71 positive clones (from 150 total) and were able to eliminate 50% as false positives. The remaining clones will be tested and then the true positive gene sequences will be analyzed and known genes identified by referencing the citrus gene database. Postharvest Methods to Control Citrus Black Spot (CBS; Guignardia citricarpa): Two sets of in vivo experiments were conducted using large numbers of naturally infected fruit. Fresh Valencia oranges from a block infected with citrus black spot (Guignardia citricarpa) were harvested and evaluated for presence/absence of CBS lesions and equal numbers of randomized fruit were distributed among the different treatments. Fruit were treated with one of seven fungicides at ambient or heated temperatures. The fungicides include azoxystrobin, fludioxonil, pyrimethanil, phosphorous acid, Imazalil, thiabendazole, and sodium-o-phenylphenate. Each of these have formulations that are registered for postharvest use on citrus. Control fruit were either left dry or dipped in water alone. After treatments, the fruits were air dried and kept at 25 C, 70% relative humidity, 3 ppm ethylene, and continuous light condition to promote CBS lesion development. Some significant differences were found among the fungicide treatments. Carvacrol was identified last season as a promising candidate for killing Guignardia citricarpa in the lab. Experiments were expanded with additional in vitro and in vivo tests during the current reporting period. We found that certain concentrations of carvacrol completely inhibit mycelium growth in vitro 14 days after incubation. Transferring mycelium plugs of the highest concentration to fresh PDA medium did not grow again (were killed). Carvacrol was also tested on fruit from CBS-infected Valencia orange blocks. Fruit that had no obvious CBS lesions (asymptomatic) and were dipped in either a carvacrol solution reduced subsequent lesion development by 87% compared to the control. Heated carvacrol solutions gave no additional benefit. Synthetic carvacrol, which is much less expensive than the natural material, is just as effective. Studies were also conducted that found the additional of eugenol to carvacrol increased inhibition activity of carvacrol on mycelium growth at the same concentration, with higher concentration having a greater effect.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2014
Citation:
Baldwin, E.A., J. Bai, A. Plotto, and M.A. Ritenour. 2014. Citrus Fruit Quality Assessment; Producer and Consumer Perspectives. Stuart Postharvest Review 2:1-7
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2014
Citation:
Kim, D.G., T.F. Burks, M.A. Ritenour, and J. Qin. 2013. Citrus Black Spot Detection Using Hyperspectral Imaging. Proc. Fla. State. Hort. Soc. 126:172-179
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2014
Citation:
Ritenour, M.A., J. Yancy, L. Pilon, and J. Narciso. 2013. Effectiveness of harvesters at identifying and removing citrus fruit with canker symptoms in the field. Proc. Fla. State. Hort. Soc. 126:253-256
- Type:
Other
Status:
Published
Year Published:
2014
Citation:
Danyluk, M.D., M.A. Ritenour, R. Goodrich, and K, Schneider. 2014 Water and FSMA. Citrus Industry, Dec, 95(12):16-18. Southeast AgNET Publications
- Type:
Other
Status:
Published
Year Published:
2014
Citation:
Schneider, K.R., R. Goodrich Schneider, M.A. Ritenour, M.D. Danyluk, and S. Richardson. 2014 The Food Safety Modernization Act and the FDA Facility Registration Program. Citrus Industry, May, 95(5):16. Southeast AgNET Publications
- Type:
Other
Status:
Published
Year Published:
2014
Citation:
Ritenour, M.A. 2014. 2014 Florida Citrus Pest Management Guide: Fresh Fruit Pesticide Residue Limits. IFAS Fact Sheet HS-1124.
Updates from changes throughout the year are posted at http://irrec.ifas.ufl.edu/postharvest/index/pesticides.shtml
|
Progress 10/01/12 to 09/30/13
Outputs
Target Audience: The primary audiences for this information have been growers, harvesters, packers, and shippers of fresh citrus. Fellow researchers are also an audience to spur scientific discussion and the development of future experiments. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided? Conferences attended: 3rd International Research Conference on HLB, Orlando, FL – February 2013 Florida State Horticultural Society annual meetings, Sarasota, FL – June 2013 American Society for Horticultural Sciences annual meetings, Palm Desert, CA – July 2013 Hosted Dr. Guixin Chen as a visiting scientist to study gene expression of fruit that develop granulation. He trained laboratory personnel on molecular techniques to compare gene expression in healthy vs. granulated fruit tissues. Dr. Chen received training in postharvest physiology and handling of citrus (and other fresh commodities) in Florida. He participated in a week-long Postharvest Industry Tour that Drs. Ritenour and Sargent co-lead each spring. How have the results been disseminated to communities of interest? Presentations: Pesticide Residue Tolerances in Domestic & Export Markets. Biopesticides and Residue Management, Feb. 2013, Webinar. Field and Packing Facility Sanitation. Part of the workshop, “Hazard Analysis, Risk-Based Preventive Control Safety Plan for Fresh Produce”, Feb. 2013, Athens, GA. An Objective Method to Measure Peelability of Citrus Fruit. American Society for Horticultural Sciences Annual Meeting, July 2013, Palm Desert, CA. Controlling Early Season Brown Rot on Fresh Citrus. Fifty-Second Annual Citrus Packinghouse Day, Aug. 29, 2013, Lake Alfred, FL. US Food Safety Update. Southern Agribusiness Services, CCA/CEU Agronomic Seminar. March 26, 2013, Sebring, FL. Effectiveness of Harvesters at Identifying and Removing Fruit with Canker Symptoms in the Field. Florida State Horticultural Society Annual Meetings, June 2013, Sebring , FL. Correct Identification of Citrus Fruit Diseases. Presented to 3 different industry groups within the state. Principles of Good Food Safety/Hygiene. Presented to 17 different industry groups within the state. Principles of Good Personal Hygiene. Presented to 2 different industry groups within the state. OSHA Standard Changes Resulting from the Globally Harmonized System. Presented to 6 different industry groups within the state. Worker Protection Standard. Presented to 1 industry group within the state. The presentations on correct identification of citrus disease was as part of team of UF/IFAS research and Extension faculty and was part of 20 workshops conducted during the current reporting period throughout different citrus growing regions of Florida, training approximately 1,647 workers from 42 different companies. In all, approximately 4099 laminated sheets, posters and other visual aids illustrating and contrasting symptoms of citrus canker and citrus black spot with various defects and diseases that are not of quarantine significance. These workshops have become an annual program and are an important contributor to preventing infected fruit from being shipped to restrictive export markets. Such markets have never reported finding citrus canker or black spot on fresh citrus from Florida. Often during the same training program, we also gave presentations on good food safety/hygiene and personal hygiene. During the current reporting period, 14 of the 16 (88%) Indian River Citrus League packinghouses participated in the training programs, plus two others located in Polk County. More than 46 individual companies/businesses participated, resulting in 1,445 documented and trained employees in Food Safety. What do you plan to do during the next reporting period to accomplish the goals? Evaluate and develop ways to control citrus black spot symptom development on harvest fruit. Research will continue evaluating in vitro effects of essential oils, heat, fungicides, and systemic acquired resistance inducing compounds, but will also combine treatments (e.g., heated fungicides) and will evaluate treatments on actual symptomatic and asymptomatic fruit from a block with heavy citrus black spot infection. In addition to potassium phosphite, expanded evaluations will be conducted with heated fungicide solutions to control a broader range of postharvest decays in fresh Florida citrus. Postharvest evaluations of new fresh fruit selections will continue and factors that influence fruit peelability will be expanded to more varieties and how peelability changes during maturation.
Impacts
What was accomplished under these goals?
Heated Potassium Phosphite Solutions to Control Brown Rot (Phytophthora citrophthora) Development on Citrus Fruit: Late-summer rains that occur in Florida commonly spread fungal spores that result in the development of brown rot after harvest of fresh citrus. Previously, only preharvest copper or potassium phosphite sprays were recommended for reducing the occurrence of the disorder. During this reporting period, experiments were conducted on Murcott tangerine, Valencia and Navel oranges, and Ruby Red grapefruit evaluating the effectiveness of heated (49C) or non-heated solutions of either potassium or calcium phosphite at controlling this disorder. Results demonstrated that potassium phosphite solutions provided good postharvest control of this disorder, especially if the solutions were heated. Calcium phosphite often also significantly reduced brown rot development, but was not as effective as potassium phosphite. Quantifying and Evaluating Ease-of-Peeling (Peelability) of Fresh Citrus: Ease of peeling is an important trait of new cultivars. To objectively measure this trait of different cultivars or after various fruit treatments or storage, we developed a peelability tester. During the current reporting period, we determined that using a continuous strip of peel cut around the equator, with cross cuts on opposite sides of the fruit that allowed up to 30 mm of peel to be pulled away from the segments, gave representative results for the whole fruit. Tests comparing grapefruit and orange found, as expected, that ‘Valencia’ oranges required greater force (both peak and average) for peel removal, and that the peel would break after shorter distances than with grapefruit. Additional tests with ‘Marsh’ grapefruit, ‘Murcott’ tangerines, and navel oranges found that colder (5C) fruit required greater force for peel removal and resulted in easier peel breakage than warmer (22 or 35C) fruit. In these tests, ‘Murcott’ tangerines peeled easiest, followed by navel oranges, and then ‘Marsh’ grapefruit. Postharvest Methods to Control Citrus Black Spot (CBS; Guignardia citricarpa): Benzaldehyde, citral, carvacrol, cinnamaldehyde, eugenol, eucalyptol, and trans-cinnamaldehyde were evaluated for in vitro activity against G. citricarpa isolated from infected citrus fruit. After repeated experiments, we found that exposure to 25, 50, or 100 mg/l carvacrol volatiles prevented growth of the pathogen on PDA for 14 days within the chambers, while the same concentrations of citral inhibited growth by 60% to 90%. Exposure to carvacrol did not kill the pathogen, however, as mycelium grew again when transferred to fresh PDA media. Exposure to benzaldehyde, trans-cinnamaldehyde, and cinnamaldehyde volatiles also inhibited mycelial growth, but were progressively less effective. Eucalyptol and eugenol were not effective in reducing growth, but eucalyptol did alter the pathogens morphology and decreased pycnidium formation. Thus, at this point we have at least one promising candidates to help control G. citricarpa, especially if combined with another treatment (e.g., heat or fungicide). Initial experiments testing G. citricarpa growing on PDA plates held at 50, 35, or 20C, were repeated. To improve the precision of short term heat exposure, G. citricarpa mycelium was cultured in 20 ml PDB liquid medium for 7 days. After 7 days, a small mess of mycelium accumulated in the liquid medium. The flasks with SDW were placed in random positions in a hot water bath at 25 (control) or 55C. For each treatment, a mycelial mass was placed in the flasks at the different temperatures for 0.5, 1, 2, 3, 4, 5, or 6 min. After the designated time, the flasks were removed and placed immediately in cold water. The mycelium mass was then placed on PDA medium and its growth observed during incubation at 25 C. Preliminary results suggest that inhibition of mycelial growth increased as treatment time increased from 30 sec to 1 min, but additional heat exposure was only marginally effective as exposure time was extended to 6 min. Exposure times of 1 to 2 min could be incorporated into existing postharvest operations. Preliminary in vitro test of chitosan (a reported inducer of systemic acquired resistance) demonstrated no ability to inhibit G. citricarpa mycelial growth. Future studies will evaluate if chitosan can stimulate resistance of citrus peel tissue to G. citricarpa infection or growth within the tissue. Postharvest Evaluation of Advanced Selections from the UF IFAS Citrus Breeding Program: A total of 27 different mandarin, orange, and grapefruit/pummelo hybrids were evaluated during the reporting period. The fruit were evaluated for external (fruit weight, size, color, peel puncture resistance) and internal (Brix, titratable acidity, ratio, juice content) quality evaluations and the remaining fruit were evaluated weekly or biweekly during cold storage for decay, peel breakdown, and the development of physiological disorders. Important varietal responses and differences were detected.
Publications
- Type:
Conference Papers and Presentations
Status:
Awaiting Publication
Year Published:
2014
Citation:
Kim, D.G., T.F. Burks, and M.A. Ritenour. 2013. Citrus Black Spot Detection Using Hyperspectral Imaging. Proc. Fla. State. Hort. Soc. 125: (in press)
- Type:
Conference Papers and Presentations
Status:
Awaiting Publication
Year Published:
2014
Citation:
Ritenour, M.A., J. Yancy, L. Pilon, and J. Narciso. 2013. Effectiveness of harvesters at identifying and removing citrus fruit with canker symptoms in the field. Proc. Fla. State. Hort. Soc. 125: (in press)
- Type:
Other
Status:
Published
Year Published:
2014
Citation:
Ritenour, M.A. 2013. Minimizing postharvest peel breakdown of fresh citrus. Citrus Industry, Oct., 94(10):20-22. Southeast AgNET Publications
- Type:
Other
Status:
Published
Year Published:
2013
Citation:
Richardson, S., R. Goodrich-Schneider, M.A. Ritenour, M.D. Danyluk, and K.R. Schneider. 2013 The Food Safety Modernization Act and the FDA Facility Registration Program. IFAS Fact Sheet FSHN13-07 http://edis.ifas.ufl.edu/fs231
- Type:
Journal Articles
Status:
Published
Year Published:
2013
Citation:
Bulanon, D.M., T.F. Burks, D.G. Kim, M.A. Ritenour. 2013. Citrus Black Spot Detection using Hyperspectral Image Analysis. Agricultural Engineering International: the CIGR Ejournal 15:171-180.
- Type:
Journal Articles
Status:
Published
Year Published:
2013
Citation:
Niphadkar, Nikhil P., T.F. Burks, J. Qin, M.A. Ritenour. 2013. Estimation of citrus canker lesion size using hyperspectral reflectance imaging. International Agricultural Engineering Journal 22:41-51.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2012
Citation:
Gaver, T., J. Burrow, D. Cole, C. Kelly-Begazo, K. Lenfesty, and M. Ritenour. 2012. The Fresh Citrus Traveling Road Show. Proc. Fla. State. Hort. Soc. 125:400
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2012
Citation:
Ritenour, M.A., C. Hu, and J. Narciso. 2012. Continuing the Search for an Effective Preharvest Fungicide with Residual Postharvest Diseases Control for Fresh Florida Citrus. Proc. Fla. State. Hort. Soc. 125:248-251
|
Progress 10/01/11 to 09/30/12
Outputs
OUTPUTS: Peel breakdown of citrus: Conducted three field experiments evaluating the effects of different pre-harvest foliar nutritional, antitranspirant, or other coating treatments on citrus postharvest peel breakdown. Treatments included K (mono-potassium phosphate), Vapor Gard (an antitranspirant), WashGard (a carnauba formulation), or Polymer Delivery System (a proprietary adjuvant). Results from these tests were presented at the annual American Society for Horticultural Sciences meetings (July 2012) and a manuscript is in preparation. Preventing Shipment of Citrus Fruit with Canker Symptoms: Citrus canker and Citrus Black Spot are important disease of quarantine significance that, if found, disqualifies the fruit for shipment to some important export markets (i.e., those of the European Union). As part of team of UF/IFAS research and Extension faculty and support personnel, we conducted 10 workshops throughout different citrus growing regions of Florida, training approximately 1,478 workers (up from 1,050 the previous year) from 37 different companies. In all, approximately 4,451 laminated sheets, posters and other visual aids illustrating and contrasting symptoms of citrus canker and citrus black spot with various defects and diseases that are not of quarantine significance. Postharvest Evaluation of Advanced Selections from the UF IFAS Citrus Breeding Program: A total of 45 different mandarin, orange, and grapefruit/pummelo hybrids were evaluated during the reporting period. The fruit were evaluated for external (fruit weight, size, color, peel puncture resistance) and internal (Brix, titratable acidity, ratio, juice content) quality evaluations and the remaining fruit were evaluated weekly or biweekly during cold storage for decay, peel breakdown, and the development of physiological disorders. Important varietal responses and differences were detected. Ease of peeling is an important trait of new cultivars. To objectively measure this trait of cultivars, we developed a peelability tester and began using the tests on some of the selections. By the end of the season we had refined the procedure. Besides the early experiments developing the mechanics of the tests and tests on the cultivars, we ran four experiments evaluating peelability using strips of peel from the top vs. bottom vs. equatorial portions of the fruit. Subsequent adjustments allowed evaluation of longer strips of peel to better evaluate peel integrity (the length of continuous peel that can be removed before breakage). We modified a clamp system to hold the fruit that allows the fruit to rotate as the peel is being pulled so that the angle of pulling remains constant throughout the process. A series of tests during the summer and fall also evaluated the effects of fruit temperature on peelability. PARTICIPANTS: Dr. Mark Ritenour - PI Cuifeng Hu - Biological Scientist (technician) - Assisted in all experimental setup, administering treatments, and data collection, analysis, and summarization Xiaojing Yu -Graduate Student. Activities associated with peel breakdown of citrus were part of her Masters project. Cassie Young - Part time assistant. General assistance with data collection and fruit evaluation Mac Hossain - Part time assistant. General assistance with data collection and fruit evaluation Andrew Myers - Part time assistant. General assistance with data collection and fruit evaluation University of Florida, Citrus Research and Education Center, Lake Alfred. Dr. Megan Dewdany - Extension outreach collaborator Jamie Burrow - Extension outreach collaborator University of Florida, Agricultural and Biological Engineering, Gainesville. Thomas Burks - Research collaborator USDA, ARS, Fort Pierce Dr. Jan Narciso - Research collaborator Dr. Eddie Stover - Research collaborator Dr. T. Greg McCollum - Research collaborator TARGET AUDIENCES: The primary audiences for this information are growers, harvesters, packers, and shippers of fresh citrus. Fellow researchers are also an audience to spur scientific discussion and the development of future experiments. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Preventing Shipment of Citrus Fruit with Canker Symptoms: Knowledge gained after evaluating the data over three seasons showed: Slower line speeds (6.1 m per min) allowed significantly better detection of canker lesions than faster speeds (i.e., 12.2 m per min). Depending on the condition of the fruit, a typical commercial operation might run fruit past graders at 9.1 m per min. Greater lighting intensities between 1,000 and 2,000 lux only occasionally improved canker detection at the highest value. However, some graders commented of excessive glare at 2,000 lux. A typical commercial operation often provides about 1,000 lux to the grading table. Each additional grader, from 1 to 3, significantly increased the removal percentage of fruit with canker symptoms. Sixty five percent of the fruit with canker were correctly identified and removed when three graders evaluated the fruit. While this may appear like a relatively low percentage, keep in mind that an average of 22 graders evaluate the fruit on each Florida packingline. There was no significant difference in the percentage of canker removal when the overall percentage of symptomatic fruit was 2% or 5%. However, significantly more fruit with canker were left undetected as the abundance of symptomatic fruit increased to 10% or 20%. Roller color had no significant effect on the ability of graders to correctly identify grapefruit with canker lesions. With each additional canker lesion per fruit, graders were 2.8% more likely to identify the fruit as having canker and removing it. In the same way, increasing canker lesion size by 1 mm resulted in a 6.2% increase in the likelihood of detecting it on the grading line. Industry training workshops for correctly identifying citrus canker and citrus black spot were conducted throughout different citrus growing regions of Florida, These workshops have become an annual program since Citrus Canker became established in Florida in 2006 and are an important contributor to preventing infected fruit from being shipped to restrictive export markets. As a result, such restrictive markets have never reported finding citrus canker or black spot on fresh citrus from Florida.
Publications
- Qin, J., T.F. Burks, X. Zhao, N. Niphadkar, and M.A. Ritenour. 2012. Development of a two-band spectral imaging system for real-time citrus canker detection. Journal of Food Engineering 108:87-93.
- Narciso J.A., C. Ference, M. Ritenour, and W.W. Widmer. 2012. Effect of copper hydroxide sprays for citrus canker control on wild type Escherichia coli. Letters in Applied Microbiology, 54(2):108-111.
- Hu, C., M.A. Ritenour, and E. Rosskopf. 2011. Trichoderma Rot on 'Fallglo' Tangerine Fruit in Florida. Proc. Fla. State. Hort. Soc. 124:232-234
- Ritenour, M.A., J. Zhang, M.M. Dewdney, and J. Narciso. 2012. Decay Control of Fresh Citrus. Citrus Industry, Oct., 93(10):6-10. Southeast AgNET Publications
- Yu, X. and M.A. Ritenour. 2012. The Effect of Preharvest Coatings and Foliar Nutritional Sprays on Postharvest Peel Breakdown of Citrus Fruit. HortScience 47(9):S251. (Abstr.)
- Ritenour, M.A., J. Yancy, L. Pilon, C. Hu, J. Narciso, and T. Burks. 2012. Optimum Grading Conditions for Identifying Lesions of Citrus Canker Xanthomonas citri subsp. citri, Xcc) on Grapefruit. HortScience 47(9):S251. (Abstr.).
- Stover, E., G. McCollum, J. Chaparro, and M. Ritenour. 2012. Under Severe Citrus Canker and HLB Pressure, Triumph and Jackson are More Productive than Flame and Marsh Grapefruit. FSHS 2012 Program and Abstracts; available at http://www.fshs.org/.
- Ritenour, M.A. and C. Hu. 2012. Continuing the Search for an Effective Preharvest Fungicide with Residual Postharvest Diseases Control for Florida Fresh Citrus. FSHS 2012 Program and Abstracts; available at http://www.fshs.org/.
- Kim, D.Q., T.F. Burks and M.A. Ritenour . 2012. Citrus Black Spot Detection Using Hyperspectral Imaging. FSHS 2012 Program and Abstracts; available at http://www.fshs.org/.
- Gaver, T., J. Burrow, D. Cole, C. Kelly-Begazo, K. Lenfesty, and M. Ritenour. 2012. The Fresh Citrus Traveling Road Show. FSHS 2012 Program and Abstracts; available at http://www.fshs.org/.
|
Progress 10/01/10 to 09/30/11
Outputs
OUTPUTS: Preventing Shipment of Citrus Fruit with Canker Symptoms: Two separate experiments were conducted during the reporting period to determine optimum grading methods to remove symptomatic fruit. The first experiment utilized three laboratory employees as graders, whereas three commercial graders hired from a commercial packinghouse graded fruit during the second experiment. Before running the fruit on the grading line, the washed grapefruit were previously evaluated for canker and other peel disorder/disease such as melanose, windscar, anthracnose and leafminer. The canker-infected fruit were also evaluated for the number of lesion and minimum and maximum size of lesion. Each fruit was labeled with a unique ID and tagged with a bar code for rapid scanning during the grading process. Initial evaluation of the data was begun. Preliminary analysis shows that, as expected, greater removal of canker-infected fruit was achieved when more graders were added to the grading line, and that greater rates of canker infection decrease the ability of graders to identify and remove all the fruit with canker symptoms. It appears that perhaps only 60% of the fruit with canker symptoms were removed when up to the three graders were present, which should not be alarming because a survey suggests that commercial packinglines utilize an average of 22 graders. On the other hand, very little sound fruit (without canker symptoms) were mistakenly removed by the graders. There were some significant differences between grading effectiveness related to roller color within a particular experiment, but variability between experiments meant that results overall did not appear significant. Additional analysis is currently underway, such as evaluating the effect of lesion size on grader effectiveness and any differences between experiments. During training workshops throughout the state for correctly distinguishing Citrus Canker and Citrus Black Spot (CBS), 1,144 laminated Packinghouse Citrus Canker Fruit ID Sheets, 1,830 Identification of Early CBS Symptoms, and 1,468 Packinghouse CBS Identification sheets were distributed, and 182 CBS Identification Posters were handed out in English, and 41 in Spanish. Reducing Canker Infection in the Field Utilizing Mixtures of Fruit Coatings and Copper: Three field-based experiments were conducted to evaluate the effectiveness of copper hydroxide combined with coating materials of WashGard or experimental materials from JBT FoodTech compared to commercial control methods. Forty fruit were flagged on each replicate tree within all three experiments and evaluated for canker development on fruit. When combined with copper, WashGard and one of the experimental JBT coating formulations significantly reduced canker lesions compared to the grower standard in the one block with relatively high levels of canker, whereas there were no significant treatment effects in the other two plots with relatively low levels of canker infection. PARTICIPANTS: University of Florida, Indian River Research and Education Center, Fort Pierce. Dr. Mark Ritenour - PI Cuifeng Hu - Biological Scientist (technician) - Assisted in all experimental setup, administering treatments, and data collection, analysis, and summarization Jordan Yancy - Part time assistant. Assisted primarily with the canker grading experiments; experimental setup, administering treatments, and data collection, analysis, and summarization Cassie Young - Part time assistant. General assistance with data collection and fruit evaluation Joseph Harris - Part time assistant. General assistance with data collection and fruit evaluation Andrew Myers - Part time assistant. General assistance with data collection and fruit evaluation University of Florida, Citrus Research and Education Center, Lake Alfred. Dr. Megan Dewdany - Extension outreach collaborator Jamie Burrow - Extension outreach collaborator USDA, ARS, Fort Pierce Dr. Jan Narciso - Research collaborator Dr. T. Greg McCollum - Research collaborator Dr. Erin Rosskopf - Research collaborator TARGET AUDIENCES: The primary audiences for this information are growers, harvesters, packers, and shippers of fresh citrus. Fellow researchers are also an audience to spur scientific discussion and the development of future experiments. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Preventing Shipment of Citrus Fruit with Canker Symptoms: As part of a team of trainers, we conducted 15 workshops throughout many citrus growing regions of Florida, training approximately 1,050 workers from 38 different companies. The participants were diverse, with approximately 50% being Hispanic (trained in Spanish), 10% African American, and 35% white. All participants were also given laminated sheets illustrating various citrus diseases symptoms on fresh citrus (including Citrus Canker and Citrus Black Spot). Citrus canker and Black Spot are important disease of quarantine significance that, if found, disqualifies the fruit for shipment to important export markets (i.e., those of the European Union). These annual workshops are an important reason for Florida's perfect record of preventing fruit with diseases such as Citrus Canker or Black Spot from being shipped to markets prohibiting these diseases. Reducing Canker Infection in the Field Utilizing Mixtures of Fruit Coatings and Copper: Several leading fresh citrus growers are now adding WashGard to their copper sprays with reported positive results. Statistics on sprayed acreage is not yet available.
Publications
- Simonne, A.H. and M.A. Ritenour. 2011. Citrus. P. 90-117. In: L.A. Terry (ed.). Health-promoting properties of fruits and vegetables. CABI Publishing, CAB International, Wallingford, UK.
- Qin, J., T.F. Burks, X. Zhao, N. Niphadkar, and M.A. Ritenour. 2011. Multispectral Detection of Citrus Canker Using Hyperspectral Band Selection. Transactions of the American Society of Agricultural and Biological Engineers (ASABE), 54(6):1-11.
- McCollum, T.G., C.J. Hearn, and M. Ritenour. 2010. Maturity and postharvest performance of 'US Early Pride' seedless mandarins. Proc. Fla. State. Hort. Soc. 123:274-277
- Ritenour, M.A., L. Pilon, R. Muraro, J. Narciso, and T.F. Burks. 2010. Commercial postharvest practices used to handle fresh citrus fruit with canker symptoms. Proc. Fla. State. Hort. Soc. 123:255-258
- Sambhav, M.A. Ritenour, C. Hu, F.G Gmitter, W.S. Castle, and J.W. Grosser. 2010. Effects of growing location, storage temperature, and fruit coating on postharvest quality and quality retention of 'Sugar Belle' mandarin. Proc. Fla. State. Hort. Soc. 123:234-237
- Danyluk, M., R. Goodrich, and M.A. Ritenour. 2011. Implications of the Food Safety Modernization Act on Florida Citrus. Citrus Industry, Oct., 92(10):18-19. Southeast AgNET Publications
- Ritenour, M. 2011. Preserving Appeal: Act early to help reduce peel breakdown of fresh citrus. Florida Grower, July, 104(7):20-21. Meister Media Worldwide.
- Ritenour, M.A. and M.M. Dewdney 2010. Fresh citrus issues: Black Spot, Canker, & MRLs. Citrus Industry, Oct., 91(10):18-19. Southeast AgNET Publications
- Ritenour, M.A., J. Zhang, and M. Dewdnew. 2011. Postharvest decay control recommendations for Florida citrus fruit. IFAS Fact Sheet CIR359A. http://edis.ifas.ufl.edu/ch081.
- Ritenour, M.A. 2010. 2011 Florida Citrus Pest Management Guide: Fresh Fruit Pesticide Residue Limits. IFAS Fact Sheet HS-1124. http://edis.ifas.ufl.edu/cg087.
- Dewdney, M.M., J.D. Yates, and M.A. Ritenour. 2011. Identification of Early Citrus Black Spot Symptoms / Identificacion de los Sintomas iniciales de la Mancha Negra de los Citricos. IFAS Fact Sheet PP-295. http://edis.ifas.ufl.edu/pp285.
- Ritenour, M, M. M. Dewdney, N. A. Peres, and J. D. Yates. 2010. Packinghouse Citrus Black Spot ID / Identificacion de la Mancha Negrade los Citricos en las Plantas de Procesamiento. IFAS Fact Sheet HS1184. http://edis.ifas.ufl.edu/hs1184.
- Hu, C., E. Rosskopf, and M.A. Ritenour. 2011. Trichoderma Rot on 'Fallglo' Tangerine Fruit. FSHS 2011 Program and Abstracts; available at http://www.fshs.org/.
|
|