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Submitted to: European Journal of Plant Pathology
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 8/30/1996 Publication Date: N/A Citation: N/A Interpretive Summary: Spring blackstem and leafspot of alfalfa, caused by the fungus Phoma medicaginis is responsible for economically important losses of mature plants. This fungus can be carried on the seed but it is not known whether airborne spores of P. medicaginis can attack alfalfa plants. A study was undertaken to determine the influence of several factors on degree of infection. It was found that susceptibility to infection increased with seedling age and that the degree of infection was always higher in two susceptible alfalfa cultivars compared to two moderately resistant ones. Levels of infection increased with increasing length of the incubation period (i.e. 48, 72, or 96 hours). In practical terms, this means that unless a prolonged period of wet, cloudy weather follows planting, there is a very good chance that alfalfa seedlings will not be infected by P. medicaginis. The data also show that moderate resistance can be overcome given a sufficiently long and favorable incubation period. This information is useful for plant pathologists and plant breeders working with alfalfa. Technical Abstract: Spring blackstem and leafspot of alfalfa, incited by Phoma medicaginis, is known to cause economically important losses of mature plants. This fungus can be seedborne but it is not known whether non-seedborne P. medicaginis can attack alfalfa seedlings. A study was undertaken to determine the influence of several factors on degree of infection. It was found that susceptibility to infection increased with seedling age and that the degree of infection was always higher in two susceptible cultivars compared to two moderately resistant ones. Levels of infection increased with increasing length of the incubation period (i.e. 48, 72, or 96 hours). In practical terms, this means that unless a prolonged period of wet, cloudy weather follows planting, there is a very good chance that alfalfa seedlings will not be infected by P. medicaginis. The data also show that moderate resistance can be overcome given a sufficiently long and favorable incubation period. |
