Cff

Cff was first discovered in South Dakota, U.S. in the 1920s and has since been recorded in several countries, including Canada, Mexico, Brazil, Australia and Iran. In Europe and Africa, its occurrence is more restricted, with reports from countries like Romania and Russia.

Biology

Cff resides within the xylem vessels of plants, where it interferes with water transport, causing wilting. It primarily spreads through infected seeds but can also be transmitted via irrigation water and plant debris.

Symptoms

Cff causes wilting of leaves and stems due to disrupted water transport, interveinal chlorosis that can progress to necrotic areas and leaf flaccidity. Additionally, the edges of leaves may appear scorched and shriveled, and infected seeds can show discoloration, turning yellow, orange, pink or purple, particularly in white-seeded varieties.

Damage

Yield losses can be substantial, with productivity reductions of up to 90% reported in some instances.

Management

Seed testing and Idaho quarantine prevent the spread of Cff, protecting bean crops from bacterial wilt. Plant certified, disease-free seeds and treat them with bactericides like streptomycin. Rotate beans with non-host crops for two to three years and use resistant varieties. Practice good sanitation by incorporating infected residues into the soil and removing volunteer plants. Avoid reusing contaminated irrigation water and maintain field hygiene by not working in wet fields to prevent spreading the bacteria.

Further reading

• Curtobacterium flaccumfaciens pv. flaccumfaciens — EPPO datasheets on pests recommended for regulation
• Bacterial wilt of dry beans caused by Curtobacterium flaccumfaciens pv. flaccumfaciens: A new threat from an old enemy
• Compendium of bean diseases, 2nd edition

Pesticide warning

Always read and follow the instructions printed on the pesticide label. The pesticide recommendations in this University of Idaho webpage do not substitute for instructions on the label. Pesticide laws and labels change frequently and may have changed since this publication was written. Some pesticides may have been withdrawn or had certain uses prohibited. Use pesticides with care. Do not use a pesticide unless the specific plant, animal or other application site is specifically listed on the label. Store pesticides in their original containers and keep them out of the reach of children, pets and livestock.

Trade names — To simplify information, trade names have been used. No endorsement of named products is intended nor is criticism implied of similar products not mentioned.

Groundwater — To protect groundwater, when there is a choice of pesticides, the applicator should use the product least likely to leach.