| Abstract Detail
Plant Protection Kirk, William W [1], Douches, David [2], Thill, Christian [3], Thompson, Asunta L [4], Hammerschmidt, Ray [1], Berry, Devan [1], Schafer, Rob [1]. Evaluation of potato late blight management utilizing host plant resistance and reduced rates and frequencies of fungicide applications; 2004-05. FIELD experiments were carried out (2004-2005) to evaluate the efficacy of combining host resistance with reduced rates and frequencies of the residual contact fungicide fluazinam to control foliar potato late blight (Phytophthora infestans). Potato cultivars (cvs.) and advanced breeding lines (ABL) developed in four states were used in combination with fluazinam applications at 0, 33%, 50%, 66% and 100% of the manufacturer recommended application rate (MRAR) applied at 5, 7, 10 or 14 day application intervals. Values of relative area under disease progress curve (RAUDPC) in the untreated plots demonstrated that cvs. and ABL were significantly different in susceptibility to late blight. The cv. Jacqueline Lee was used as a resistant reference and the cvs. Snowden and FL 1879 as susceptible. Reduced amounts of fluazinam were either fully or partially effective at most application rates tested on all cultivars/ABL compared to the non-treated controls. However. in some cultivars/ABL, 50% of the MRAR of fungicide was sufficient to achieve acceptable control, whereas other cultivars/ABL required 100% MRAR to control late blight. On late blight susceptible cultivars, applications of fluazinam at either 10 or 15-day intervals were usually partially effective for controlling late blight at the doses tested. However, in the resistant cultivars Torridon and MSJ461-1 the fungicides did not reduce the RAUDPC in comparison with untreated plots of these cultivars and fungicides are not required for late blight control in these entries. The study demonstrates that potato cvs./ABL with reduced susceptibility to late blight can be managed with reduced fungicide rates and longer application intervals, thus offering a less expensive option for potato late blight control.
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1 - Michigan State University, Plant Pathology, 35 Plant Biology Building, Wilson Road, East Lansing, MI, 48824, United States
2 - Michigan State University, Department of Crop and Soil Sciences, 499B Plan and Soil Sciences Building, East Lansing, Michigan, 48824, United States
3 - University of Minnesota, Horticultural Science, 305 Alderman Hall, St. Paul, MN, 55108, US
4 - North Dakota State University, Plant Sciences, Loftsgard Hall, Fargo, ND, 58105, US
Keywords:
disease
advanced breeding lines.
Session: Poster-4
Location: Ballroom CD/Monona Terrace
Date: Tuesday, July 25th, 2006
Time: 8:00 AM
Abstract ID:106 |
