May 1, 2003

 

Good News for Sugarbeet Growers

From 1996 to 2001, American Crystal Sugar Company (ACSC) suffered losses of approximately $50 million dollars as a result of root rot caused by Aphanomyces, according to Michael Metzger, North Dakota State University graduate student -- plant pathology.

Aphanomyces cochlioides, a water mold that affects sugarbeets in both the seedling and adult stages, took its toll again in 2002, as ACSC shareholders abandoned nearly 20,000 acres of rotten sugarbeet.

Such substantial losses have ignited aggressive research in the area of controlling Aphanomyces. One related trial performed by Metzger and John Weiland, USDA Agricultural Research Service plant pathologist, has demonstrated the potential effectiveness of biological treatments and induced resistance in reducing losses to root rot.

In 2001 and 2002, randomized block design plots were established near Hillsboro, N.D. and Perley, Minn. to perform field evaluation of varied treatments.

According to Metzger and Weiland’s report, medium-sized seed of Maribo 9369 was treated with the bacterium Burkholderia cepacia AMMDR1 at approximately 7.5 log colony forming units per seed. The same treatment was applied for Pseudomonas fluorescens PRA25rifz.

During the 2001 growing season, the control seed was not treated with any bacterium nor was any of the seed treated with Apron™ (Metalaxyl), Thiram™ (Thiram), or Tachigaren™ (hymexazol). In 2002, however, three different seed variables were used including all three of the above seed fungicides.

Stand counts were taken at 15, 30 and 45 days after planting, as well as a final count on the center two rows at harvest.

In 2001, foliar applications of formulated harpin protein (MessengerTM) were applied weekly beginning immediately after seedling emergence and continued for 12 consecutive weeks. During the 2002 season, Messenger™ was applied 4, 8, and 12 consecutive weeks after seedling emergence.

At harvest, each sugarbeet root was visually rated for Aphanomyces Root Rot before being bagged and transported to the Minn-Dak Farmers Cooperative Tare Lab in Wahpeton, N.D. for quality and purity analysis.

Metzger notes that although the research produced varying data, the general effects of biological control and induced resistance were favorable. "Taking a look at the 2001 data, both the Messenger and bacterial treatments yielded beets that out-produced the untreated check," he says.

The B. cepacia AMMDR1 treated seed produced a yield of 10.95 tons per acre, and the plots that received weekly applications of Messenger yielded 13.98. In comparison, the untreated plot yielded only 7.81 tons per acre. "Similar trends were observed in the 2002 trial," Metzger says.

In addition, sugar percentages increased slightly, as impurities decreased with biological control. However, the levels were not particularly significant.

Nevertheless, Metzger and Weiland’s research indicates that root rot can be reduced by using biological treatments alone or in conjunction with chemical applications; thus, greater yields are attainable. The good news for growers? Higher per acre returns.

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Source: Mike S. Metzger, (701) 671-1355, mmetzger@minndak.coop
John J. Weiland, (701) 239-1373, weilandj@fargo.ars.usda.gov
Writer: Teresa Oe, (701) 231-8371, teresa.oe@ndsu.nodak.edu
Editor: Rich Mattern, (701) 231-6136, richard.mattern@ndsu.nodak.edu