@article{stahr_quesada-ocampo_2021, title={Effects of Water Temperature, Inoculum Concentration and Age, and Sanitizers on Infection of Ceratocystis fimbriata, Causal Agent of Black Rot in Sweetpotato}, volume={105}, ISSN={["1943-7692"]}, url={https://doi.org/10.1094/PDIS-07-20-1475-RE}, DOI={10.1094/PDIS-07-20-1475-RE}, abstractNote={ Black rot, caused by Ceratocystis fimbriata, is a devastating postharvest disease of sweetpotato that recently re-emerged in 2014. Although the disease is known to develop in storage and during export to overseas markets, little is known as to how pathogen dispersal occurs. This study was designed to investigate dump tank water as a means of dispersal through four different types of water treatments: inoculum concentration (0, 5, 5 × 101, 5 × 102, and 5 × 103 spores/ml), inoculum age (0, 24, 48, 96, and 144 h), water temperature (10°C, 23°C, 35°C, and 45°C), and presence of a water sanitizer (DryTec, SaniDate, FruitGard, and Selectrocide). Wounded and nonwounded sweetpotato storage roots were soaked in each water treatment for 20 min, stored at 29°C for a 14-day period, and rated for disease incidence every other day. Disease was observed in sweetpotato storage roots in all water treatments tested, except in the negative controls. Disease incidence decreased with both inoculum concentration and inoculum age, yet values of 16.26% and up to 50% were observed for roots exposed to 5 spores/ml and 144-h water treatments, respectively. Sanitizer products that contained a form of chlorine as the active ingredient significantly reduced disease incidence in storage roots when compared with control roots and roots exposed to a hydrogen-peroxide based product. Finally, no significant differences in final incidence were detected in wounded sweetpotato storage roots exposed to water treatments of any temperature, but a significant reduction in disease progression was observed in the 45°C treatment. These findings indicate that if packing line dump tanks are improperly managed, they can aid C. fimbriata dispersal through the build-up of inoculum as infected roots are unknowingly washed after storage. Chlorine-based sanitizers can reduce infection when applied after root washing and not in the presence of high organic matter typically found in dump tanks. }, number={5}, journal={PLANT DISEASE}, publisher={Scientific Societies}, author={Stahr, Madison N. and Quesada-Ocampo, Lina M.}, year={2021}, month={May}, pages={1365–1372} }
 @article{stahr_quesada-ocampo_2020, title={Assessing the Role of Temperature, Inoculum Density, and Wounding on Disease Progression of the Fungal Pathogen Ceratocystis fimbriata Causing Black Rot in Sweetpotato}, volume={104}, ISSN={["1943-7692"]}, url={https://doi.org/10.1094/PDIS-12-18-2224-RE}, DOI={10.1094/PDIS-12-18-2224-RE}, abstractNote={ In 2014, Ceratocystis fimbriata, causal agent of black rot in sweetpotato, reemerged and inflicted large financial losses on growers in the United States. Black rot continues to damage sweetpotatoes and has become a priority to the industry since then. In contrast, little is known about the biology of C. fimbriata and the epidemiology of sweetpotato black rot. In this study, effects of environmental factors such as inoculum density, RH, and temperature on sweetpotato black rot were determined. Cured sweetpotatoes were wounded with a toothpick to simulate puncture wounds, inoculated with different spore suspensions (inoculum density) (104, 105, or 106 spores/ml), and incubated under different RH (85.53, 94.09, or 97.01%) and temperature (13, 18, 23, 29, or 35°C) for 21 days. In a separate experiment, five root wounding types (cuts, punctures, abrasions, end breaks, and macerating bruises) were compared. All wounded roots were subsequently soaked in a 103 spores/ml suspension and incubated at 100% RH and 23°C for 21 days. This study found 29 and 23°C to be the optimal temperature for black rot disease development and sporulation, respectively. No pathogen growth was observed at 13 and 35°C. Increased inoculum density significantly (P < 0.0001) increased disease incidence, but increasing RH had an effect only on sporulation area. All wound types resulted in increased disease incidence and sporulation as early as 7 days postinoculation. Our results highlight the importance of characterizing factors that affect disease development for achieving successful disease management strategies. Findings from this study will be used to improve disease management for sweetpotato black rot by suggesting tighter regulation of curing and storage conditions and better postharvest handling of sweetpotato roots to avoid unnecessary wounding. }, number={3}, journal={PLANT DISEASE}, publisher={Scientific Societies}, author={Stahr, M. and Quesada-Ocampo, L. M.}, year={2020}, month={Mar}, pages={930–937} }
 @article{stahr_quesada-ocampo_2019, title={Black Rot of Sweetpotato: A Comprehensive Diagnostic Guide}, volume={20}, ISSN={["1535-1025"]}, DOI={10.1094/PHP-08-19-0052-DG}, abstractNote={ Black rot of sweetpotato (Ipomoea batatas) has been considered one of the most historically devastating diseases of the crop. The pathogen, Ceratocystis fimbriata (Ellis and Halst), is able to infect a variety of hosts including morning glory (Ipomoea sp.), coffee (Coffea sp.), and mango (Mangifera indica) over a wide geographic range. The slow-growing nature of the pathogen can lead to difficulty in isolating and maintaining cultures of the fungus. Thus, the objective for this diagnostic guide is to provide information about effective techniques for pathogen isolation, identification, storage, and pathogenicity testing as well as describe the host and geographic range, taxonomy, and disease in sweetpotato. }, number={4}, journal={PLANT HEALTH PROGRESS}, author={Stahr, Madison N. and Quesada-Ocampo, Lina M.}, year={2019}, pages={255–260} }