Effect of Fungicides on Sugar Beet Yield and Quality.

North Dakota and Minnesota produce more than 50% of the United States sugar beet, Beta vulgaris, production. The objective of this research was to determine the effect of fungicides on sugar beet yield and quality in the absence of disease.  Sugar beet was planted at Prosper, North Dakota in 2005, 2006 and 2007.  The variety selected was tolerant to Aphanomyces cochlioides and seeds were treated with Tachigaren to give additional protection from Aphanomyces. Weeds were controlled using recommended practices.  The fungicides Eminent, Headline, Gem, Super Tin and Topsin were each applied three times at about 14 days intervals starting in late July.  There was also an untreated control.  Treatments were arranged in a randomized complete block design with four replicates.  Roots were harvested, weighed, and analyzed in late September.  There were no significant differences in recoverable sucrose or sucrose concentration between the untreated control and any of the fungicide treatments.  In 2007, root samples were collected, washed and placed in polyethylene bags and stored at 4ºC and high relative humidity.  Mean respiration rates were determined after 30 and 90 days in storage.  There was no significant difference in respiration rate between the untreated control and any of the fungicide treatments.  In the absence of disease, there was no benefit in applying fungicides to sugar beet.