Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC 27695-7616.
Plant Dis. 2020 Mar;104(3):930-937. doi: 10.1094/PDIS-12-18-2224-RE. Epub 2020 Jan 28.
In 2014, , 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 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) (10, 10, or 10 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 10 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 ( < 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.
2014 年，甘薯黑斑病的病原菌再次出现，给美国种植者造成了巨大的经济损失。此后，黑斑病继续损害甘薯，并成为该行业的首要任务。相比之下，人们对甘薯黑斑病的生物学和流行病学知之甚少。在这项研究中，确定了环境因素（如接种密度、相对湿度和温度）对甘薯黑斑病的影响。用牙签刺伤已治愈的甘薯以模拟刺伤，用不同的孢子悬浮液（接种密度）（10、10 或 10 个孢子/ml）接种，并在不同的相对湿度（85.53、94.09 或 97.01%）和温度（13、18、23、29 或 35°C）下孵育 21 天。在另一个实验中，比较了五种根伤类型（切割、刺伤、磨损、末端断裂和粉碎性瘀伤）。所有受伤的根随后浸泡在 10 个孢子/ml 的悬浮液中，并在 100%相对湿度和 23°C 下孵育 21 天。本研究发现 29°C 和 23°C 分别是黑斑病发展和孢子形成的最佳温度。在 13°C 和 35°C 下未观察到病原体生长。接种密度的增加显著（<0.0001）增加了疾病发病率，但相对湿度的增加仅对孢子形成面积有影响。所有伤口类型在接种后 7 天内都会导致疾病发病率和孢子形成增加。我们的研究结果强调了对影响疾病发展的因素进行特征描述的重要性，以实现成功的疾病管理策略。本研究的结果将用于通过建议更严格地控制甘薯的治愈和储存条件，以及更好地处理甘薯根以避免不必要的伤口，来改善甘薯黑斑病的管理。
