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Sugarbeet Crop Progress (06/25/20)

The growth stage of the sugarbeet crop in most areas in North Dakota and Minnesota is dependent on the date the crop was planted.

The growth stage of the sugarbeet crop in most areas in North Dakota and Minnesota is dependent on the date the crop was planted. At southern Minnesota Beet Sugar Cooperative, planting started and was completed the earliest so the crop is most advanced in that area followed closely by the Minn-Dak Factory District. The earliest planted beets are closing rows or will be closing rows in about 7 to 10 days. In the American Crystal Sugar Company growing area, planting date was later and over a longer period of time. As such, there are areas in the Central Red River Valley that have beets at the 4-6 leaf stage and areas in the southern Red River Valley where rows will be closing by July 4th (Figure 1). There are some areas that were affected by dry conditions after planting and other areas with too much rainfall where the plant stand may be lower than our ideal 175 to 200 plants per 100 ft of 22 inch rows. However, fields with lower populations will still have good yields with good pest management and will require some more care and patience at harvesting.

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Most growers who produce beets in the Northern Red River Valley where the Sugarbeet Root Maggot is a problem have applied one or two insecticide applications to manage the flies and maggots; some growers will be applying insecticides this week (June 21 to 27) to make sure that maggots do not impact their crop.

Growers, especially in the southern production areas, have to start Cercospora control early. In areas with a history of severe disease and high inoculum population from previous years, fungicide applications should start as soon as the rows are closed and the environment becomes warm and wet, or as soon as we observe the first symptoms – which are a few brown or gray spots or lesions about 1/8 of an inch in diameter (Figure 2), appearing first on the oldest leaves.

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In principle, growers must mix two different modes of action in each of their applications to get effective leaf spot control in 2020. Tin and triazole fungicides are the mainstay of our program and these should always be mixed with other chemistries including ethylenebisdithiocarbamates (EBDCs) such as mancozeb and penncozeb, and copper fungicides. The fungicides that are most at risk for the Cercospora fungus (Cercospora beticola) to develop fungicide resistance are the triazoles (or demethylation inhibitors DMIs) and quinone outside inhibitos (QoIs or strobilurins). As such, these fungicides (Inspire XT, Eminent, Proline, Provysol, Minerva, Lucento, Enable, Topguard, Headline, Gem, Priaxor) should be used at full rates even when in mixtures. Growers should consult their agriculturists for the best recommendations for their respective growing districts based on known sensitivity to different fungicides.

 

Mohamed Khan

Extension Sugarbeet Specialist

NDSU & U of MN

218-790-8596

This site is supported in part by the Crop Protection and Pest Management Program [grant no. 2017-70006-27144/accession 1013592] from the USDA National Institute of Food and Agriculture. Any opinions, findings, conclusions, or recommendations expressed are those of the website author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture.

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