Abstract
Seed tubers of susceptible and moderately resistant cultivars were inoculated withPhytophthora infestans and planted in a field in four trials over three years. After emergence, the foliage was periodically examined for late blight lesions. For the four trials, blight was first observed 9, 5,4, and 4 days after the accumulation of 18 severity values supporting the use of severity values for the prediction of initial appearance of blight as used in Blitecast. The first observance of blight followed a period of consecutive days which were favorable for blight development and ranged from 17 to 46 days after median emergence. Lesions were observed on foliage of the susceptible cultivars before detection on moderately resistant cultivars for three out of four trials. We conclude that late blight will usually, but not always, appear in susceptible cultivars before it appears in moderately resistant ones.
Compendio
Se inocularon conPhytophthora infestans tubérculos-semillas de cultivares susceptibles y moderadamente resistentes que se sembraron en cuatro ensayos de campo durante tres años. Después de la emergencia, el follaje fue examinado periódicamente para detectar lesiones de trizón tardío. El tizón fue observado por primera vez a los 9,5,4 y 4 días después de la acumulación de 18 valores de severidad que apoyan el uso de los valores de severidad para la predicción de la aparición inicial del tizón tal como son utilizados en estados avanzados de la enfermedad. La primera observación del tizón se realizó después de un periodo de días consecutivos que fueron favorables para su desarrollo y que varió de 17 a 46 días despuéés de la emergencia media. En tres de los cuatro ensayos, las lesiones sobre el follaje de los cultivares susceptibles fueron observadas antes que sobre el follaje de los cultivares moderadamente resistentes.
Podemos concluir que el tizón tardio, por lo general, pero no siempre, aparecerá antes en los cultivares susceptibles que en los moderadamente resistentes.
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Doster, M.A., Sweigaird, J.A. & Fry, W.E. The influence of host resistance and climate on the initial appearance of foliar late blight of potato from infected seed tubers. American Potato Journal 66, 227–233 (1989). https://doi.org/10.1007/BF02853445
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DOI: https://doi.org/10.1007/BF02853445