May 24, 2001

Recent Rains Both A Positive And Negative For Sugarbeet Growers

Recent rains in the Red River Valley could be viewed as a negative in getting the remaining sugarbeets into the ground but Art Lamey, North Dakota State University Extension plant pathologist, has a different view. "Recent rains actually were a positive in some areas because we were getting some crusting problems," says Lamey. "The rains helped soften up the soil surface making it easier for the sugarbeets to emerge."

But the recent rains have some sugarbeet growers concerned about seedling diseases especially Aphanomyces, Rhizomania and Pythium. "It could be especially serious if it suddenly gets very hot," says Lamey. "Wet soil combined with higher soil temperatures are conditions that favor the development of these diseases.

Of more concern to Lamey is the development of Aphanomyces. "It can be devastating at anytime but it is particularly bad when it comes in the seedling stage. You can have a severe stand loss which we’ve seen in recent years."

Lamey says seed pelleting with Tachigaren is effective against Aphanomyces for about 3 to 4 weeks. Aphanomyces has been a problem in the past in southern Minnesota. About 99 percent of the seed in that area has been pelletized with Tachigaren. "My concern is further up the Red River Valley," says Lamey. "The further north you go the less you’ll find seed that has been pelletized."

Rhizomania may also be a problem to some sugarbeet growers. Rhizomania is a viral disease but is carried by a water mold notes Lamey. So conditions that favor Aphanomyces also are conducive to Rhizomania. It can cause stunting of young plants. There are resistant varieties available but are used primarily in southern Minnesota.

Some growers have tried to do some cultivating to dry out the soil. "Since these are water molds, by the time the grower is able to get into the field to cultivate, the damage is already done," says Lamey. "So how much good tillage does is really an open question."

Pythium usually attacks just before seedling emergence or shortly after. However, most seeds are treated with Apron which is highly effective against Pythium.

Lamey says seedling disease relates more to prevention rather than being able to do something about it after it has occurred. "If a grower has a serious problem with Aphanomyces this year, it would be a good idea to have soil samples taken and an Aphanomyces assay run before planting beets on that ground in future years. This will help growers determine whether they have a serious enough problem to warrant the use of a resistant variety and Tachigaren or perhaps wait another couple of years before planting sugarbeets at all."

More information on growing sugarbeets is available on the Web at http://www.ag.ndsu.nodak.edu/media/beets/sgrbeet.htm .

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