• The Plant Pathology Journal
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• v.27 no.3
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• pp.232-341
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• 2011

Pink snow mold, caused by Microdochium nivale, is a major disease on cool season turfgrasses in golf courses in northern Unites States. The relative susceptibility of 17 commercial cultivars of three bentgrass species (creeping, colonial and velvet bentgrass) to Microdochium nivale and the aggressiveness of M. nivale eight isolates obtained from infected turfgrasses on golf courses in Wisconsin were evaluated under controlled conditions. For the field trial, susceptibility of 2 year-old 12 commercial bentgrass cultivars was evaluated after inoculating three M. nivale isolates in the fields. There were significant differences in disease severities among the three bentgrass species, particularly between tetraploids (creeping and colonial) and diploid (velvet) species, and among cultivars within each species, indicating that there are varying levels of susceptibility in species and cultivars to M. nivale. Host resistance by days of cold hardening was confirmed, by detecting the resistance by 30 days of cold hardening treatments. In field trial, susceptibility of 12 bentgrass cultivars was highly correlated to the results obtained from growth chamber experiments. The positive correlation of the susceptibility between growth chamber experiments and field trials demonstrates that the growth chamber method is a useful technique for saving time, space and labor to evaluate efficiently pink snow mold susceptibility of bentgrass cultivars. This study could be applied to evaluating susceptibility of bentgrass to pink snow mold and also predicting a prospective evaluation of bentgrass cultivars to pink snow mold in fields in a breeding program.

• Asian Journal of Turfgrass Science
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• v.25 no.2
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• pp.177-183
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• 2011

The susceptibility of cultivars of three bentgrass species (creeping, colonial, and velvet bentgrass) was evaluated on detached leaves assays with pink snow mold 9 isolates caused by Microdochum nivale in Petri dishes and whole plants under controlled conditions. The pink snow mold isolates obtained from infected turfgrasses on golf courses in Wisconsin were tested on response of fungicides and temperature. Detached leaf assay and susceptibility of bentgrass cultivars were evaluated with potted adult seeding during 80 days. Nine isolates were susceptible to two fungicides and were significantly different among isolates. Mycelial growth was varied in response of temperatures among isolates. There were significant differences in development and colonization of the fungus on detached leaf assay among bentgrass species include culvitars. There were significant differences on whole plants in disease severities among the three bentgrass species, particularly between tetraploids (creeping and colonial) and diploid (velvet) species, and among cultivars within each species, indicating that there are varying levels of susceptibility in species and cultivars to M. nivale. This study could be applied to evaluate the susceptibility of bentgrass to pink snow mold and also to predict a prospective evaluation of bentgrass cultivars to pink snow mold in fields in a breeding program.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2005.04a
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• pp.7-8
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• 2005

• The Plant Pathology Journal
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• v.25 no.1
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• pp.6-12
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• 2009

Snow molds are the most important winter diseases of turfgrass in the United States and Canada. Eight isolates of three snow mold fungal species (three isolates of Typhula ishikariensis, three of T. incarnata, and two of Microdochium nivale) were collected from infected turfgrasses on golf courses. The isolates were evaluated for their relative aggressiveness on three cultivars (L-93, Penncross, and Providence) of creeping bentgrass (Agrostis palustris) under the same controlled conditions. Four plant ages (15, 19, 23 and 27 week-old plants from germination to inoculation) were evaluated for their susceptibility to the three pathogens and for the recovery of the plants. Regardless of age or cultivar of the host plant, M. nivale was found to be more aggressive and faster to infect and colonize than Typhula species. After three weeks recovery, M. nivale-inoculated plants showed higher disease severity than plants inoculated with the two Typhula species. Plants infected by Typhula species displayed no significant difference in disease severity. As creeping bentgrass plants get older, the severity of disease caused by three snow molds gradually decreases. This effect was observed in all cultivars tested, suggesting expression of age-related resistance as the bentgrass plants matured.

• Journal of Microbiology and Biotechnology
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• v.5 no.6
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• pp.341-345
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• 1995

Seventy four microorganisms, which have antagonistic activity against to Fusarium culmorum, were tested for their inhibitory effect on colony development of obligate biotroph Erysiphe graminis f. sp. hordei Marchal, the causal agent of powdery mildew on barley plants. Of these, 13 actinomycetes isolates were shown to reduce the colony development of mildew completely by application of their 10% cell-free culture filtrates on barley leaves. An Isolate, A252, was the most powerful antagonist and its antifungal activity was further assessed. The colony development of mildew was significantly reduced by application of the 1% cell-free culture filtrate of isolate A252. In comparison to the control, the protective and curative application of 10% cell-free culture filtrate from A252 showed 88.5% and 96.1% reduction of colony numbers respectively. By the protective application, 68.3% of the inhibition was observed after 9 days of treatment, thus showed prolonged inhibitory effect. In vitro test, complete inhibition of the mycelial growth of Microdochium nivale was achieved by the treatment of 1% A252 culture filtrate and 80.2% of inhibition was observed by the 0.1% treatment.