2008 Cercospora Resistance Maps

Comments for 2008 Cercospora Maps

Cercospora Sensitivity/Resistance for Eminent 2007 versus 2008

There was a significant reduction in isolates that were resistant to Eminent in the Drayton, East Grand Forks, Crookston and Hillsboro districts in 2008. In these districts the only area of concern is from Crookston to East Grand Forks along highway 2.

Resistance levels are much higher in the Moorhead district. Incidence of resistance is higher in Clay and Cass counties than was observed in 2007. Southern Clay county is of particular concern and needs to be watched carefully in the future.

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Cercospora Sensitivity/Resistance 2007-2008 Comparison for Headline

There were 31 locations with documented partial resistance to Headline in 2007, but only 5 in 2008. However 3 locations showed resistance to Headline in 2008 versus none in 2007.

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Cercospora Tolerance for TPTH-2008

There were no locations in any factory district with any documented tolerance to the tin fungicides in 2008. In two spray programs tin followed by Headline may be a good option in Cass and Clay counties. When Minndak discontinued use of Eminent for one season almost all of the resistance observed the previous year disappeared.

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