September 13, 2001

Anthracnose Found in Pintoba Pinto Beans

Anthracnose, a serious dry edible bean disease, has been recently detected in a number of north central North Dakota fields planted to Pintoba pintos. Collected samples have been identified by a crop consultant, the NDSU plant diagnostician, the NDSU bean plant pathologist and State Seed Department officials according to Duane R. Berglund, NDSU Extension agronomist.

Anthracnose was found primarily in Pintoba pintos with original seed source believed to be from Manitoba, Canada. The fungal disease is seed-borne, but can survive in the field on plant residues and on infected beans left in the field. The pathogen can survive on stored beans for two years or more. It can and will attack other classes and susceptible varieties of dry beans. It may already exist in other classes or varieties and just hasn’t been identified in 2001 fields according to Berglund. Yield reduction and reduced quality is the major concern of this disease. Bean anthracnose is not toxic and is not a food safety issue for human consumption, he adds.

Anthracnose spreads during cool wet weather by rain splash or center pivot irrigation. It also can be spread by harvest equipment movement through the fields. Humans and animals may also spread the disease when walking through fields if the foliage of the bean plants are wet.

Berglund encourages all dry bean seed processors and commercial elevators accepting Pintoba pintos to check the seeds carefully. All culls and cleanout of infected beans should be discarded and destroyed. The infected seeds can be a source of infection. Producers with suspected anthracnose infected pintos should deliver to a processor and inform them of the possibility of infection and a need to handle the beans carefully.

The following Best Management Practices (BMP’s) for control and elimination of bean anthracnose from Northarvest production areas are recommended:

• Harvest the anthracnose infected fields last
• Clean harvest equipment throughly when moving from field to field and before all transport
• Custom harvest equipment must be cleaned and sanitized
• Bin all infected beans separately from other fields
• Culls and cleanout should be destroyed by producers or bean processors
• Clean tillage -- Incorporate all plant residues and beans with immediate fall tillage following harvest using a moldboard plow or heavy discing.
• Avoid bin run seed for planting in 2002
• Have all suspected seed tested for bean anthracnose (several samples should be submitted) The North Dakota State Seed Department can test for this disease.
• Plant certified seed which is tested to verify it is anthracnose free
• Purchase from reputable dealers
• Rotate to beans three full years after anthracnose infection occurs
• Control and eliminate volunteer beans in 2002
• Alert neighbors of any infected anthracnose fields

Using common sense is the best way to control and eliminate the disease says Berglund. Use high quality certified bean seed. Seed treatment is not completely effective to control bean anthracnose, and currently no fungicide seed treatment is labeled for use in the United States. Using resistant varieties are the best answer to its ultimate control.

The North Dakota State Seed Department field inspectors have been checking certified dry bean seed production fields and have not found any evidence of anthracnose in 2001 fields regardless of class or variety. All bean seed going through the certification process must also pass the laboratory tests.

The practice of saving and replanting commercial beans (bin run) maybe the worst economic decision bean growers can make for the 2002 growing season says Berglund.

Berglund says the Northarvest Bean Growers, North Dakota State Seed Department, North Dakota Dry Edible Bean Seed Growers Association and NDSU are all highly concerned and motivated to control bean anthracnose in North Dakota. For additional information contact : Duane Berglund, NDSU Plant Science Dept. (701-231-8135, Luis del Rio NDSU Plant Pathology Dept. ( 701-231-7073), or Ken Bertsch, North Dakota State Seed Dept. ( 701-239-7210).

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Source: Duane R. Berglund, (701) 231-8135, dberglun@ndsuext.nodak.edu
Luis del Rio, (701) 231-7073, Luis.delRio-Mendoza@ndsu.nodak.edu
Editor: Rich Mattern (701) 231-6136, Richard_Mattern@ndsu.nodak.edu