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A postharvest rot of ripe sweet pepper fruits was found in Kagawa Prefecture in western Japan in October 2002. A fungus, isolated repeatedly from the diseased fruits and identified as Fusarium lactis, was demonstrated to be pathogenic on wounded fruits of sweet pepper. The disease was diagnosed as an internal fruit rot that had been noted abroad. The disease and the fungus were judged new in Japan. The fungal isolate was also pathogenic on wounded fruits of tomato and eggplant.

Brown lesions were found on leaves of the weed barnyardgrass in paddy fields in Hiroshima Prefecture in western Japan in June 2017. A fungus, isolated repeatedly from diseased plants and identified as Exserohilum oryzicola, was demonstrated to be pathogenic to barnyardgrass. The disease was diagnosed as leaf spot, reported abroad but new to Japan. In pathogenicity tests, the isolate was also pathogenic to barley, bread wheat, durum wheat, and rice but foliar symptoms were milder than on barnyardgrass; it was nonpathogenic on soybean.

Blighting of lower sheaths was found on barley, bread wheat and durum wheat grown in western Japan in April 2014, May 2016, and April 2019, respectively. A fungus, isolated repeatedly from the diseased plants and identified as Ceratobasidium cereale, was demonstrated to be pathogenic to the three crops. The diseases, new in Japan, were diagnosed as sharp eyespot that had been noted abroad.

A soil inhabiting fungus, Ophiosphaerella korrae (J. Walker & A.M. Sm. bis) Shoemaker & C.E. Babc. has been confirmed to be pathogenic to barley, durum wheat and bread wheat of the major crops (Hong et al., 2018; Tomioka et al., 2019ab). Foliage and spikes of the affected plants early blight with root rot and ripening disorder. In this study, we revealed virulence of the fungus to rice, which is also one of the major crops. When a rice cultivar (cv. Norin No. 22) was grown in pots in artificial climate chambers after being sowed with culture discs (6 mm in diameter) of the fungus (strains MAFF150117 and MAFF150118 from bread wheat and durum wheat, respectively) on synthetic nutrient agar (SNA) (1 disc per seed), growth delay and early foliage blight (including ripening disorder) with rotting of roots and stem bases occurred. Defect rates were 22% and 84% for the plants inoculated with strains MAFF150117 and MAFF150118, respectively. Control plants simultaneously treated with aseptic SNA discs had no symptom. The fungal strains were consistently isolated from all the inoculated plants, but not from healthy controls, demonstrating that the fungal strains were virulent to rice. Additionally, a decrease tendency of grain yield without symptom on foliage and roots was detected on a rice cultivar (cv. Koshihikari that is cv. Norin No. 1 × cv. Norin No. 22) inoculated with strain MAFF150117 in another pot experiment. Ophiosphaerella korrae is also known as a pathogen causing spring dead spot or necrotic ring spot of Bermudagrass (Wetzel et al., 1999ab; Camara et al., 2000; Iriarte et al., 2004; Gullino et al., 2007; Perry et al., 2010; Sasaki et al., 2010), Kentucky bluegrass (Wetzel et al., 1999a; Camara et al., 2000, 2001; Hayakawa et al., 2004; Wong et al., 2015), Louisiana grass (Wetzel et al., 1999a; Camara et al., 2000) and Zoysiagrass (Hayakawa et al., 2004; Tredway and Butler, 2007). We will investigate varietal difference against O. korrae as well as the fungal emergent ecology in the future.[References] Camara et al. (2000) Mycologia 92:317-325 Camara et al. (2001) Mycol Res 105:41-56 Gullino et al. (2007) Pl Dis 91:1200 Hayakawa et al. (2004) J Jpn Soc Turf Sci 33 (Supplement 1):24-25 Hong et al. (2018) Pl Dis 103(1):158 Iriarte et al. (2004) Pl Dis 88:1341-1346 Perry et al. (2010) Mycopathologia 169:395-402 Sasaki et al. (2010) Jpn J Phytopathol 76(3):158 Tomioka et al. (2019a) Abstracts of papers presented at the 44th annual meeting of the pesticide science society of Japan, p 82 Tomioka et al. (2019b) Abstracts of papers presented at the 63th annual meeting of the mycological society of Japan, p 64 Tredway and Butler (2007) Pl Dis 91:1684 Wetzel et al. (1999a) Mycol Res 103:981-989 Wetzel et al. (1999b) Pl Dis 83:1160-1166 Wong et al. (2015) Pl Pathol 44:545-555

Severe wilt was found on seedlings of turnip green (Brassica rapa L., perviridis group) in Ibaraki Prefecture, Japan, from May to September 2013. A fungus repeatedly isolated from diseased plants was identified as Rhizoctonia solani AG-4 HG-III based on culture morphology, anastomosis and sequencing of the internal transcribed spacer region on ribosomal DNA (rDNA-ITS region). Pathogenicity of this isolate to turnip green was confirmed based on inoculation test. Because Rhizoctonia blight of turnip green by AG-4 HG-III has not been reported so far, we propose including it as one of the pathogens causing this disease.

Rotting of roots and stem bases and wilting of entire plants were found on a gentianaceous flowering plant, prairie gentian (Eustoma grandiflorum), grown in Kagawa Prefecture in the southwest region of Japan in April 2001. A mitosporic fungus, isolated repeatedly from the diseased plants, was identified as a species belonging to the clade 3 of Fusarium solani species complex based on the morphology and the sequence of the translation elongation factor gene. It was demonstrated to cause the disease by inoculating potted plants and reisolating the fungus from the diseased plants. We propose the name “Fusarium root rot of prairie gentian” for this disease.

Severe spotting and blight of leaves caused by Colletotrichum destructivum were found on snapdragon (Antirrhinum majus L.), a scrophulariaceous ornamental, in open fields in Shizuoka Prefecture, Japan, from June through September 2004. The fungus is added to the group of the pathogens causing anthracnose of snapdragon.

Foliar wilt as well as crown and root rot with sclerotia formation has affected potted liver leaf (Hepatica nobilis var. japonica f. magna) in Ojiya, Niigata Prefecture, Japan, since 2006. Apothecia developed from the sclerotia on soil surface of pots with the diseased plants in March. A fungus forming the apothecia was identified as Dumontinia tuberosa (Sclerotiniaceae) based on its morphology and demonstrated to cause the disease. We coined the name “Dumontinia root rot (Dumontinia-negusare-byo in Japanese) of liver leaf” for the new disease.

In some areas of Japan, yellow spots with white pustules on leaves, stems, petioles, peduncles and calyces were found on Ipomoea nil, I. triloba, I. lacunosa and I. hederacea var. integriuscula. We demonstrated that the diseases on I. nil, I. triloba and I. lacunosa were caused by host-specific strains of Albugo ipomoeae-panduratae and defined three forma speciales of the fungus, respectively, for the three Ipomoea species: “f. sp. nile”, “f. sp. trilobae” and “f. sp. lacunosae”. Because the diseases were new to Japan, we coined the Japanese name “shirosabi-byo”, which means white rust. We also showed that the disease on I. hederacea var. integriuscula was caused by A. ipomoeae-hardwickii. We named this new disease “white rust (shirosabi-byo in Japanese)”.

Based on inoculation experiments and morphological studies on the pathogenic isolates of Plectosporium spp., Microdochium blight (Hakuhan-byo in Japanese) of pumpkin (Cucurbita maxima Duch.) occurring in Japan was reconfirmed to be caused by Plectosporium tabacinum, and seedling blight (Kabugare-byo in Japanese) of ranunculus (Ranunculus asiaticus L.) was demonstrated to be caused by P. tabacinum. Both diseases are renamed Plectosporium blight in this article. Some isolates of the fungus appeared to have host specificity, whereas the others had either weak or no pathogenicity to pumpkin and ranunculus.

In the central bank of the microorganisms section in the Ministry of Agriculture, Forestry and Fisheries (MAFF) Genebank in Tsukuba, 14,836 strains of fungi, bacteria, yeasts and others are preserved by various methods including cryopreservation and freeze-drying. To evaluate preservation techniques for these microorganisms, the viability of the preserved microorganisms was examined at regular intervals. Almost all tested strains, except for 5 strains out of 2,334 strains, of yeasts, bacteria and Actinomycetes were preserved well in freeze-dried form, indicating that freeze-drying is suitable for their preservation. As for fungi and Oomycetes, 6,578 strains out of 6,681 tested strains (98.5%) and 264 (63.8%) of 414, respectively, survived one-year preservation in the vapor phase of liquid nitrogen. The details on survival of the preserved fungal strains were as follows: 99.0% (1,107 strains/1,118 tested strains) survival in Ascomycota, 96.1% (1,552/1,615) in Basidiomycota, 98.6% (73/74) in Zygomycota, and 99.3% (3,846/3,874) in anamorphic fungi. Thus, cryopreservation is excellent for preservation of most fungus strains, but is not suitable for preservation of many Oomycetous strains.

Severe spotting and blighting of leaves were found on bacopa (Sutera cordata), a scrophulariaceous ornamental, in greenhouses in Gunma Prefecture, Japan, from January through February 2007. After we isolated and identified the causal fungus as Colletotrichum destructivum and inoculated host plants with the isolate to confirm pathogenicity, we named this new disease anthracnose of bacopa.

A severe rot of postharvest fruits of sweet pepper, a variety of Capsicum annuum, was found in Kagawa Prefecture in southwestern Japan in August 1999. A fungus, isolated repeatedly from the diseased fruits and identified as Stemphylium lycopersici, was demonstrated to be pathogenic to fruits of sweet pepper. The disease was new to Japan, and the fungus was added to the pathogens causing fruit rot of C. annuum.

Severe blight of potted seedlings of monkshood caused by Plectosporium tabacinum was found in glasshouses in Kagawa Prefecture in southwest Japan in May 2001. Root rot and browning of stem bases were followed by wilting and yellowing of leaves, then blighting of leaves, flower buds and stems. A fungus was isolated from diseased plants and confirmed to cause the disease. The new disease was named “Plectosporium blight of monkshood”.

In October 1998, a disease causing mainly foliar necrotic lesions was found on African marigold (Tagetes erecta) and French marigold (T. patula) grown in Miyagi Prefecture, Japan. Similar lesions also developed on stems and flowers, resulting in early blight of the affected organs. Plants with numerous lesions withered rapidly. A mitosporic fungus isolated repeatedly from the diseased plants was identified as Alternaria tagetica and demonstrated to cause the disease. The disease, as well as the fungus, is new to Japan. We propose the name “hanten-byo”, which means leaf spot in Japanese, for this disease.

Glomerella cingulata (Stoneman) Spaulding et Schrenk (anamorph: Colletotrichum gloeosporioides (Penzig) Penzig et Saccardo) has been known as the pathogen of ripe rot of grapevine (Vitis vinifera L.). In addition to this fungus, another Colletotrichum species was isolated from fruits of grape cultivar ‘Sekirei’ with ripe rot in Shimane Prefecture in 1994. Colonies of the isolate on potato dextrose agar (PDA) were reddish to pale brown. Its conidia on PDA were one-celled, hyaline, ellipsoid to fusiform with acute ends and 12-17×4-5μm. Appressoria formed on potato carrot agar were pale grayish brown, ellipsoid, rarely irregular in shape, and 8-11×4-7μm. The isolate grew slower than that of G. cingulata isolates from grape fruits on PDA at the optimum temperature. These morphological and physiological characteristics agreed with those of Colletotrichum acutatum Simmonds ex Simmonds. The ripe rot symptom was reproduced on grapevine fruits after inoculation with the isolate of C. acutatum. These results lead us to propose that C. acutatum, as well as G. cingulata, causes ripe rot of grapevine.

Stem rot and wilt of Jew’s marrow (nalta jute, Corchorus olitorius) were found on Is. Okinawa, Okinawa Prefecture, Japan, in March 2000. An anamorphic fungus, Lasiodiplodia theobromae was isolated repeatedly from the diseased plants and demonstrated to cause the disease. We coined the Japanese name “kurogare-byo” of Jew’s marrow for the present disease because it was new to Japan, although it had already been reported in India and Bangladesh as black band of the plant.