Submitted to: American Phytopathological Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 5/1/2008
Publication Date: 7/15/2008
Citation: Olanya, O.M., Honeycutt, C.W., Larkin, R.P., Griffin, T.S., He, Z., Halloran, J.M. 2008. Enhancing Potato System Sustainability: Microclimate, Early Blight and Late Blight Potential. American Phytopathological Society Abstracts. 98:S115.
Technical Abstract: Crop and soil management may modify canopy and below ground microclimate; however, their effects on potential development and control of early and late blight are not well documented. Crop management systems (Status Quo (SQ), Soil Conserving (SC), Soil Improving (SI), Disease Suppressive (DS), and continuous potato (PP)) were evaluated for their effects on microclimate, early blight potential and late blight potential under irrigated and rainfed conditions. In 2006 and 2007, microclimatic data were continuously recorded with a data logger deployed at the canopy level. Early blight was determined by visual assessment of symptoms and late blight potential was evaluated based on simulation analysis. In both years, very little variation in mean relative humidity, ambient temperature or soil temperature was detected among treatments. In 2006, soil water content was significantly higher in irrigated than in rainfed treatments in August, and ranged from -53 to -58 kPa (irrigated) compared to -90 to -130 kPa (rainfed) in DS,SQ,SC, and SI treatments. Early blight incidence and lesion numbers varied among cropping systems and between years. Disease incidence ranged from 31-64% (2006) and 12-43% (2007), and was significantly higher in PP compared to DS, SQ, SC, and SI systems. Simulated late blight development differed between years but not among cropping systems. Cropping system impacted early blight incidence, as demonstrated by more early blight detected in the PP system, compared to other systems. However, small differences in microclimate and late blight indices suggest that the cropping systems evaluated had relatively little impact on late blight potential.