Spatiotemporal distribution of diseased heads with Fusarium head blight in naturally infested wheat fields
2009
Ohsaki, M., Tokai Univ., Minamiaso, Kumamoto (Japan) | Tomimura, K. | Urano, S. | Yoshida, M. | Nakajima, T.
To understand epidemics of Fusarium head blight of wheat, we investigated the distribution of symptomatic wheat heads in a field at four times, from the first detection of the disease and then every 4 days after. The distribution of diseased heads within a field was analyzed using the Morisita index of spatial-distribution patterns. The distribution patterns of diseased heads were similar between experiments in 2004 and 2006. New diseased heads were observed 14-34 days after anthesis. The degree of clustering of diseased heads based on the Morisita index did not increase with time, but the significance of the cluster distribution did increase, suggesting that populations of the pathogen formed new independent points of clustering during the investigation. Therefore, during the life cycle of the pathogen, ascospores from the primary inoculum render new infections over long periods in fields, and conidia have a limited role in secondary infections in the disease cycle.
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