2009), lenticel spot ( Brook 1968), and lenticel breakdown ( Singh et al. Other studies proved that DCSs are also caused by physiological disorders, such as lenticel blotch pit ( Casero et al. Guthrie.), a causal fungus of bull's-eye rot ( Chen et al. (2021) recently reported that Phlyctema vagabunda Desm (syn. Winter, Brooks fruit spot caused by Mycosphaerella pomi (Pass.) Lindau, and Alternaria blotch caused by Alternaria mali Roberts. Harada and Sawamura, apple scab caused by Venturia inaequalis (Cooke) G. Tanaka, Marssonina blotch caused by Diplocarpon mali Y. and Botryosphaeria kuwatsukai (Hara) G.Y. The infectious diseases that might cause DCS development in northern Honshu Island, Japan, include bitter rot caused by the Colletotrichum gloeosporioides species complex or the Colletotrichum acutatum species complex, Botryosphaeria rot caused by Botryosphaeria dothidea (Moug.) Ces.
To prevent such damage, DCS development must be controlled following an accurate diagnosis before apples are harvested, but this is not currently done. The damaged fruits, which were sorted as a lower-grade product, were not sold as fresh apples but were used for food processing ( Narita 2005) or discarded if they were badly damaged. This major apple-growing region in Japan has 1,000.5 ha of apple orchards, including 600.5 ha used for the production of Fuji apples this information was obtained from the Horticulture Promotion Division, Department of Agriculture, Forestry and Fisheries, Akita Prefectural Government. According to a survey conducted by the Department of Agriculture and Forestry of Akita Prefecture, Japan, in 2011, apple fruits with DCSs were found in virtually every orchard in southern Akita Prefecture.
#Using 4peaks download#
Download as PowerPointĪpple fruits with DCSs at harvest time are found in many orchards worldwide ( Giraud and Bompeix 2012 Moggia and Yuri 2003 Sutton et al. Botryosphaeria dothidea, Phlyctema vagabunda, and Diplocarpon mali were detected in lesions A and B E, F, and G and D, respectively. 1).įIGURE 1 Examples of dark-colored spots (DCSs) found on Fuji apple fruits during several weeks after harvest. The lesions, called dark-colored spots (DCSs), are circular or subcircular, dark brown to black, and most are less than 5 mm in diameter ( Fig. These lesions not only significantly decrease the commercial value of apples but also serve as inocula for postharvest diseases during storage and transport if they are overlooked ( Wenneker 2019). Small lesions at early developmental stages caused by these pathogens are often found at harvest time ( Giraud and Bompeix 2012 Sutton et al. Many airborne pathogenic fungi of apple ( Malus × domestica) infect fruits as well as leaves, branches, and trunks. This is an open access article distributed under the CC BY 4.0 International license.
These results indicate that the ARISA-based technique developed in the present study is useful for the accurate, reliable, and comprehensive detection of the pathogens causing DCSs on apple fruits.Ĭopyright © 2022 The Author(s). An automated analysis of the PCR products amplified for the ARISA enables the rapid examination of many samples. Because the pathogenic fungi in the tissue underlying lesions are most likely the causal agents, these fungi could be responsible for the DCSs on apple fruits. Using this method to examine the fresh tissue of DCSs (i.e., after removing the epidermis) on commercially produced apples resulted in the detection of six fungal species and two Colletotrichum species complexes. To identify these fungi, PCR amplifications using species- or genus-specific primers were needed. However, two other species and two species complexes had similar fragment sizes. The fragment sizes for six species ( Botryosphaeria kuwatsukai, Diplocarpon mali, Mycosphaerella pomi, Neonectria galligena, Phlyctema vagabunda, and Venturia inaequalis) were unique, enabling their detection in a single ARISA trial. The fragment sizes of peaks for eight species and two species complexes that might cause DCSs on apples in northern Honshu Island, Japan, were determined on the basis of the ARISA. In this study, we conducted an automated ribosomal intergenic spacer analysis (ARISA) to reliably detect fungal pathogens in these lesions. Dark-colored spots (DCSs) found on apples at harvest time worldwide significantly reduce the commercial value of the fruits.