| Abstract Detail
Plant Protection Berry, Devan [1], Wharton, Phillip [1], Kirk, William W [1], Schafer, Rob [1], Tumbalam, Pavani [1]. Developing prediction and management systems for the control of Rhizoctonia diseases in potato based on varietal susceptibility and soil temperature. RHIZOCTONIA solani causes stem and stolon canker and black scurf on potato tubers, which can reduce plant health, yield quality and quantity. Planting decisions based upon soil temperature may reduce the severity of disease symptoms thus reducing the need for fungicide applications. A two year study was conducted in 2004 and 2005 to look at the effect of planting time (based on soil temperatures of 8, 14, and 20°C) on disease incidence and severity. Concurrently, experiments were carried out to assess the effects of a range of fungicides at 0.1, 1 and 10 ppm, on the growth of Rhizoctonia isolates in vitro at different temperatures (5, 10, 15, 20 , 25 and 30°C). In 2004, results showed that as planting temperature increased, the incidence and severity of stem canker and black scurf decreased. Average disease incidence decreased from 86 to 15% as the soil temperature at planting increased from 8 to 20oC. There were no significant differences between the 14 and 20°C planting times. In 2005, there were no significant differences in incidence and severity of black scurf among the planting temperatures. However, there was a significant difference in incidence and severity of stem canker among the different planting temperatures. The percentage of diseased stems decreased from 52% at 8°C to 11% at 20°C. Temperature x fungicide results suggest that applying fungicides at temperatures which are optimal for the growth of R. solani (between 20 - 25°C) may be less effective than applying them at lower or higher temperatures. Furthermore, in most cases the lowest concentration of fungicide (0.1 ppm) was just as effective in preventing fungal growth as the highest (10 ppm).
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1 - Michigan State University, Plant Pathology, 35 Plant Biology Building, Wilson Road, East Lansing, MI, 48824, United States
Keywords:
disease
soil borne
stem and stolon canker
black scurf.
Session: Poster-14
Location: Ballroom CD/Monona Terrace
Date: Tuesday, July 25th, 2006
Time: 8:00 AM
Abstract ID:110 |
