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Title: POTATO LATE BLIGHT MANAGEMENT IN THE TOLUCA VALLEY: FIELD VALIDATION OF SIMCAST MODIFIED FOR CULTIVARS WITH HIGH FIELD RESISTANCE

Author
item Grunwald, Niklaus - Nik
item ROMERO MONTES, G - CEEM/PICTIPAPA, MEXICO
item LOZOYA SALDANA, H - CEEM/PICTIPAPA, MEXICO
item RUBIO COVARRUBIAS, O - INIFAP, MEXICO
item FRY, W - CORNELL UNIV, NY

Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/3/2002
Publication Date: 10/1/2002
Citation: GRUNWALD, N.J., ROMERO MONTES, G., LOZOYA SALDANA, H., RUBIO COVARRUBIAS, O.A., FRY, W.E. POTATO LATE BLIGHT MANAGEMENT IN THE TOLUCA VALLEY: FIELD VALIDATION OF SIMCAST MODIFIED FOR CULTIVARS WITH HIGH FIELD RESISTANCE. PLANT DISEASE. 86:1163-1168. 2002.

Interpretive Summary: Potato late blight is a serious disease of potatoes leading to serious losses in yield and tubers in storage worldwide. Management of potato late blight in the highland tropics is very costly and remains difficult. Reducing the impact of late blight through the use of resistant cultivars in combination with a fungicide forecasting system could lower the number of costly fungicide applications. Previously, we evaluated the fungicide forecasting SimCast for use with Mexican cultivars of high levels of field resistance for use in the central highlands of Mexico and found that it predicted too many fungicide applications for cultivars of moderate to high levels of resistance. We adapted SimCast and field validations conducted in 1999 and 2000 show that SimCast resulted in good disease control on cultivars ranging form susceptible to highly resistant. The number of fungicide applications forecast for cultivars with moderate to high levels of resistance was reduced. Precipitation was the environmental variable responsible for most of the forecasts made. Our work demonstrates that a predictive system can be transferable from the temperate climate to a tropical highland climate. A user-friendly decision support system consisting of just a rain gauge and SimCast could be a valuable tool in managing potato late blight in the highland tropics. This decision support system has the potential for considerably reducing the number of fungicide applications necessary for managing potato late blight.

Technical Abstract: Management of potato late blight in the highland tropics is very costly and remains difficult. Reducing the impact of late blight through the use of resistant cultivars in combination with a fungicide forecasting system could lower the number of costly fungicide applications. Previously, we evaluated the fungicide forecasting SimCast for use with Mexican cultivars of high levels of field resistance for use in the central highlands of Mexico and found that it predicted too many fungicide applications for cultivars of moderate to high levels of resistance. We adapted SimCast and field validations conducted in 1999 and 2000, and showed the Sim Cast resulted in good disease control on cultivars ranging from susceptible to highly resistant. The number of fungicide applications forecast for cultivars with moderate to high levels of resistance was reduced. Precipitation was the environmental variable responsible for most of the forecasts made. Our work demonstrates that a predictive system can be transferable from the temperate climate to a tropical highland climate. A user-friendly decision support system consisting of just a rain gauge and the use of fungicide units might be a valuable tool in managing potato late blight in the highland tropics.