Forty-two isolates of Sclerotium rolfsii from California were grown on eight media to determine n... more Forty-two isolates of Sclerotium rolfsii from California were grown on eight media to determine nutritional conditions promoting formation of the teleomorph (Athelia rolfsii). Most of the isolates (71%) formed hymenia on PDA containing 2% activated charcoal (C-PDA). Of an additional 34 isolates from areas other than California, 17 also fruited on this medium. The extent of hymenial formation on C-PDA was influenced by the conditions of incubation and the isolate. Best results were obtained when 6 or 8 mm diam mycelial plugs taken from 8- to 10-da-old PDA cultures were used as inocula, and when dishes were incubated for 4-5 wk at 24-28 C and low light intensities. Transfer of mycelial plugs from a nutrient-rich medium, e.g., PDA, to one poorer in nutrients, e.g., Brown's medium or dilute PDA, induced fruiting in certain isolates. In general, nutritional or environmental conditions that restricted optimal growth and sclerotial production by the fungus favored hymenial formation. The salient features of the development and structure of the basidiocarp are described and illustrated. The teleomorph of the plant pathogenic fungus Sclerotium rolfsii Sacc. was first described by Goto (9) who provisionally placed it in Corticium centrifugum (Lev.) Bres. Curzi (5) later proposed that C. rolfsii should be designated as the basidial state of S. rolfsii. The teleomorph was transferred to Pellicularia by West (22), and subsequently placed in Botryobasidiulm by Venkatarayan (21). Talbot in 1973 (19) suggested that the basidial state of S. rolfsii belonged to the genus Athelia, and acting upon his suggestion, Tu and Kimbrough (20) made the combination A. rolfsii. We accept A. rolfsii (Curzi) Tu and Kimbrough as the name for the teleomorph. The teleomorph of S. rolfsii has been reported infrequently from nature (11, 22), but there are some reports of hymenial formation in culture (1, 9, 14, 15). However, in most studies, observations of fruiting have been incidental. Most workers, with the exception of Goto (10, 11) and Kulkarni and co-workers (1, 13), reported hymenial formation in two or three isolates grown on one or two media. Possible differences between isolates in their ability to fruit and the influence of media on hymenial formation, were not investigated. Moreover, the conditions that promoted formation of the basidiocarp in different isolates of S. rolfsii were never clearly described. There are few published light micrographs and no scanning electron micrographs of the teleomorph, and adequate descriptions of the development and structure of the basidiocarp are lacking, thus making identification difficult. This study was undertaken to establish the nutritional and environmental conditions that induce hymenial formation in isolates of S. rolfsii and to describe the development and structure of the basidiocarp. Seventy-six isolates from various hosts and geographical areas were tested. Media used by other workers, and additional media developed in this study, were employed. The conditions that
GC Adams Jr, WD Gubler, RG Grogan Plant Disease 71:44, 370-374, 1987. The cause of a seedling dis... more GC Adams Jr, WD Gubler, RG Grogan Plant Disease 71:44, 370-374, 1987. The cause of a seedling disease of Cucumis melo in the southern San Joaquin Valley, Kern County, California, was identified as Fusarium equiseti . ...
Forty-two isolates of Sclerotium rolfsii from California were grown on eight media to determine n... more Forty-two isolates of Sclerotium rolfsii from California were grown on eight media to determine nutritional conditions promoting formation of the teleomorph (Athelia rolfsii). Most of the isolates (71%) formed hymenia on PDA containing 2% activated charcoal (C-PDA). Of an additional 34 isolates from areas other than California, 17 also fruited on this medium. The extent of hymenial formation on C-PDA was influenced by the conditions of incubation and the isolate. Best results were obtained when 6 or 8 mm diam mycelial plugs taken from 8- to 10-da-old PDA cultures were used as inocula, and when dishes were incubated for 4-5 wk at 24-28 C and low light intensities. Transfer of mycelial plugs from a nutrient-rich medium, e.g., PDA, to one poorer in nutrients, e.g., Brown's medium or dilute PDA, induced fruiting in certain isolates. In general, nutritional or environmental conditions that restricted optimal growth and sclerotial production by the fungus favored hymenial formation. The salient features of the development and structure of the basidiocarp are described and illustrated. The teleomorph of the plant pathogenic fungus Sclerotium rolfsii Sacc. was first described by Goto (9) who provisionally placed it in Corticium centrifugum (Lev.) Bres. Curzi (5) later proposed that C. rolfsii should be designated as the basidial state of S. rolfsii. The teleomorph was transferred to Pellicularia by West (22), and subsequently placed in Botryobasidiulm by Venkatarayan (21). Talbot in 1973 (19) suggested that the basidial state of S. rolfsii belonged to the genus Athelia, and acting upon his suggestion, Tu and Kimbrough (20) made the combination A. rolfsii. We accept A. rolfsii (Curzi) Tu and Kimbrough as the name for the teleomorph. The teleomorph of S. rolfsii has been reported infrequently from nature (11, 22), but there are some reports of hymenial formation in culture (1, 9, 14, 15). However, in most studies, observations of fruiting have been incidental. Most workers, with the exception of Goto (10, 11) and Kulkarni and co-workers (1, 13), reported hymenial formation in two or three isolates grown on one or two media. Possible differences between isolates in their ability to fruit and the influence of media on hymenial formation, were not investigated. Moreover, the conditions that promoted formation of the basidiocarp in different isolates of S. rolfsii were never clearly described. There are few published light micrographs and no scanning electron micrographs of the teleomorph, and adequate descriptions of the development and structure of the basidiocarp are lacking, thus making identification difficult. This study was undertaken to establish the nutritional and environmental conditions that induce hymenial formation in isolates of S. rolfsii and to describe the development and structure of the basidiocarp. Seventy-six isolates from various hosts and geographical areas were tested. Media used by other workers, and additional media developed in this study, were employed. The conditions that
Patterns of spore release were examined for Sphaeroiheca pomosa on rose, Erysiphe pisi on pea, an... more Patterns of spore release were examined for Sphaeroiheca pomosa on rose, Erysiphe pisi on pea, and E graminis on brome-grass to determine the importance of environmental factors in removal of conidia from conidiophorcs of powdery mildews. No conidia of S. ...
Athelia arachnoidea was collected during winter on dead leaves of deciduous trees in Oregon. Minu... more Athelia arachnoidea was collected during winter on dead leaves of deciduous trees in Oregon. Minute sclerotia (0.2-1.0 mm) were seen on hyme- nia, whereas in culture sclerotia were much larger (1.0-5.0 mm). The pathogenicity, morphological characteristics, and temperature growth responses of the anamorphic state, were identical to Rhizoctonia carotae. The relationship between the sclerotial ana? morph and the teleomorph was confirmed by DNA sequence of the internal transcribed spacers of the nuclear ribosomal repeat unit. The sequences were homologous among the specimens of A. arachnoidea and the sclerotial anamorph from Oregon, A. arach? noidea and R. carotae isolates from culture collec? tions, and several isolates of R. carotae from carrot cold-storage facilities. Like R. carotae, A. arachnoidea produced abundant crystals of calcium oxalate on the hyphae, was pathogenic on carrot at 3 C, and caused crater rot symptoms equivalent in severity. Sclerotia of A. arachnoidea-R. carotae did not germi? nate under conditions suitable for eruptive germi? nation in A. rolfsii. The DNA sequence of A. epiphylla from Europe was identical (within 6 bp) to A. arach? noidea-R. carotae, whereas A. epiphylla from North America varied by 34-46 independent base pair changes. Athelia epiphylla and A. arachnoidea formed similar sclerotia. Connecting the Rhizoctonia root pathogen to the Athelia teleomorph links the dispa- rate literatures on the natural history of this fungus and reveals significant insights into the epidemiology of the disease. Fibularhizoctonia gen. nov. is proposed to encompass Rhizoctonia species with clamp connec? tions, and the description of R. carotae and R. centri- fuga are emended.
Page 1. Special Topics Environmental Factors Influencing the Formation of Basidia and Basidiospor... more Page 1. Special Topics Environmental Factors Influencing the Formation of Basidia and Basidiospores in Thanatephorus cucumeris Gerard C. Adams, Jr., and Edward E. Butler Research assistant and professor, respectively. ...
Forty-two isolates of Sclerotium rolfsii from California were grown on eight media to determine n... more Forty-two isolates of Sclerotium rolfsii from California were grown on eight media to determine nutritional conditions promoting formation of the teleomorph (Athelia rolfsii). Most of the isolates (71%) formed hymenia on PDA containing 2% activated charcoal (C-PDA). Of an additional 34 isolates from areas other than California, 17 also fruited on this medium. The extent of hymenial formation on C-PDA was influenced by the conditions of incubation and the isolate. Best results were obtained when 6 or 8 mm diam mycelial plugs taken from 8- to 10-da-old PDA cultures were used as inocula, and when dishes were incubated for 4-5 wk at 24-28 C and low light intensities. Transfer of mycelial plugs from a nutrient-rich medium, e.g., PDA, to one poorer in nutrients, e.g., Brown's medium or dilute PDA, induced fruiting in certain isolates. In general, nutritional or environmental conditions that restricted optimal growth and sclerotial production by the fungus favored hymenial formation. The salient features of the development and structure of the basidiocarp are described and illustrated. The teleomorph of the plant pathogenic fungus Sclerotium rolfsii Sacc. was first described by Goto (9) who provisionally placed it in Corticium centrifugum (Lev.) Bres. Curzi (5) later proposed that C. rolfsii should be designated as the basidial state of S. rolfsii. The teleomorph was transferred to Pellicularia by West (22), and subsequently placed in Botryobasidiulm by Venkatarayan (21). Talbot in 1973 (19) suggested that the basidial state of S. rolfsii belonged to the genus Athelia, and acting upon his suggestion, Tu and Kimbrough (20) made the combination A. rolfsii. We accept A. rolfsii (Curzi) Tu and Kimbrough as the name for the teleomorph. The teleomorph of S. rolfsii has been reported infrequently from nature (11, 22), but there are some reports of hymenial formation in culture (1, 9, 14, 15). However, in most studies, observations of fruiting have been incidental. Most workers, with the exception of Goto (10, 11) and Kulkarni and co-workers (1, 13), reported hymenial formation in two or three isolates grown on one or two media. Possible differences between isolates in their ability to fruit and the influence of media on hymenial formation, were not investigated. Moreover, the conditions that promoted formation of the basidiocarp in different isolates of S. rolfsii were never clearly described. There are few published light micrographs and no scanning electron micrographs of the teleomorph, and adequate descriptions of the development and structure of the basidiocarp are lacking, thus making identification difficult. This study was undertaken to establish the nutritional and environmental conditions that induce hymenial formation in isolates of S. rolfsii and to describe the development and structure of the basidiocarp. Seventy-six isolates from various hosts and geographical areas were tested. Media used by other workers, and additional media developed in this study, were employed. The conditions that
GC Adams Jr, WD Gubler, RG Grogan Plant Disease 71:44, 370-374, 1987. The cause of a seedling dis... more GC Adams Jr, WD Gubler, RG Grogan Plant Disease 71:44, 370-374, 1987. The cause of a seedling disease of Cucumis melo in the southern San Joaquin Valley, Kern County, California, was identified as Fusarium equiseti . ...
Forty-two isolates of Sclerotium rolfsii from California were grown on eight media to determine n... more Forty-two isolates of Sclerotium rolfsii from California were grown on eight media to determine nutritional conditions promoting formation of the teleomorph (Athelia rolfsii). Most of the isolates (71%) formed hymenia on PDA containing 2% activated charcoal (C-PDA). Of an additional 34 isolates from areas other than California, 17 also fruited on this medium. The extent of hymenial formation on C-PDA was influenced by the conditions of incubation and the isolate. Best results were obtained when 6 or 8 mm diam mycelial plugs taken from 8- to 10-da-old PDA cultures were used as inocula, and when dishes were incubated for 4-5 wk at 24-28 C and low light intensities. Transfer of mycelial plugs from a nutrient-rich medium, e.g., PDA, to one poorer in nutrients, e.g., Brown's medium or dilute PDA, induced fruiting in certain isolates. In general, nutritional or environmental conditions that restricted optimal growth and sclerotial production by the fungus favored hymenial formation. The salient features of the development and structure of the basidiocarp are described and illustrated. The teleomorph of the plant pathogenic fungus Sclerotium rolfsii Sacc. was first described by Goto (9) who provisionally placed it in Corticium centrifugum (Lev.) Bres. Curzi (5) later proposed that C. rolfsii should be designated as the basidial state of S. rolfsii. The teleomorph was transferred to Pellicularia by West (22), and subsequently placed in Botryobasidiulm by Venkatarayan (21). Talbot in 1973 (19) suggested that the basidial state of S. rolfsii belonged to the genus Athelia, and acting upon his suggestion, Tu and Kimbrough (20) made the combination A. rolfsii. We accept A. rolfsii (Curzi) Tu and Kimbrough as the name for the teleomorph. The teleomorph of S. rolfsii has been reported infrequently from nature (11, 22), but there are some reports of hymenial formation in culture (1, 9, 14, 15). However, in most studies, observations of fruiting have been incidental. Most workers, with the exception of Goto (10, 11) and Kulkarni and co-workers (1, 13), reported hymenial formation in two or three isolates grown on one or two media. Possible differences between isolates in their ability to fruit and the influence of media on hymenial formation, were not investigated. Moreover, the conditions that promoted formation of the basidiocarp in different isolates of S. rolfsii were never clearly described. There are few published light micrographs and no scanning electron micrographs of the teleomorph, and adequate descriptions of the development and structure of the basidiocarp are lacking, thus making identification difficult. This study was undertaken to establish the nutritional and environmental conditions that induce hymenial formation in isolates of S. rolfsii and to describe the development and structure of the basidiocarp. Seventy-six isolates from various hosts and geographical areas were tested. Media used by other workers, and additional media developed in this study, were employed. The conditions that
Patterns of spore release were examined for Sphaeroiheca pomosa on rose, Erysiphe pisi on pea, an... more Patterns of spore release were examined for Sphaeroiheca pomosa on rose, Erysiphe pisi on pea, and E graminis on brome-grass to determine the importance of environmental factors in removal of conidia from conidiophorcs of powdery mildews. No conidia of S. ...
Athelia arachnoidea was collected during winter on dead leaves of deciduous trees in Oregon. Minu... more Athelia arachnoidea was collected during winter on dead leaves of deciduous trees in Oregon. Minute sclerotia (0.2-1.0 mm) were seen on hyme- nia, whereas in culture sclerotia were much larger (1.0-5.0 mm). The pathogenicity, morphological characteristics, and temperature growth responses of the anamorphic state, were identical to Rhizoctonia carotae. The relationship between the sclerotial ana? morph and the teleomorph was confirmed by DNA sequence of the internal transcribed spacers of the nuclear ribosomal repeat unit. The sequences were homologous among the specimens of A. arachnoidea and the sclerotial anamorph from Oregon, A. arach? noidea and R. carotae isolates from culture collec? tions, and several isolates of R. carotae from carrot cold-storage facilities. Like R. carotae, A. arachnoidea produced abundant crystals of calcium oxalate on the hyphae, was pathogenic on carrot at 3 C, and caused crater rot symptoms equivalent in severity. Sclerotia of A. arachnoidea-R. carotae did not germi? nate under conditions suitable for eruptive germi? nation in A. rolfsii. The DNA sequence of A. epiphylla from Europe was identical (within 6 bp) to A. arach? noidea-R. carotae, whereas A. epiphylla from North America varied by 34-46 independent base pair changes. Athelia epiphylla and A. arachnoidea formed similar sclerotia. Connecting the Rhizoctonia root pathogen to the Athelia teleomorph links the dispa- rate literatures on the natural history of this fungus and reveals significant insights into the epidemiology of the disease. Fibularhizoctonia gen. nov. is proposed to encompass Rhizoctonia species with clamp connec? tions, and the description of R. carotae and R. centri- fuga are emended.
Page 1. Special Topics Environmental Factors Influencing the Formation of Basidia and Basidiospor... more Page 1. Special Topics Environmental Factors Influencing the Formation of Basidia and Basidiospores in Thanatephorus cucumeris Gerard C. Adams, Jr., and Edward E. Butler Research assistant and professor, respectively. ...
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