Computerized forecasting system (BLIGHTASIRRI) for rice sheath blight disease in the Philippines
1995
Kobayashi, T. (Tohoku Univ., Sendai (Japan). Faculty of Agriculture) | Ijiri, T. | Mew, T.W. | Maningas, G. | Hashiba, T.
A computerized forecasting system (BLIGHTASIRRI) was constructed to estimate the development of rice sheath blight disease and the yield loss associates with the disease in the Philippines. This system which describes disease development as vertical and horizontal development, was incorporated into all known data acquired from previous epidemiological studies. Vertical development expressed by the relative height of the uppermost lesions to the plant height was estimated on the basis of temperature, relative humidity and the susceptibility of rice sheath to the rice sheath blight fungus. On the other hand, horizontal development expressed by the percentage of diseased hills was determined from the combination of temperature, relative humidity and the number of sclerotia and tillers. Whole disease incidence was calculated from vertical and horizontal development by Hashiba's formula. Furthermore, to estimate the final yield loss, the relation between disease incidence and fully ripened kernels was analyzed. The model curve of vertical and horizontal development estimated by BLIGHTASIRRI was slightly different fro actual development in paddy in the wet season of 1993 and 1994. Development of this system should enable to determine the need for fungicide application
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