Bean Rust

Credits: Biovision-Infonet

Rust spots (pustules) appear on all parts above the ground. They are most numerous on leaves, particularly on the underside. They are less abundant on stems and occur sparingly on pods. Initial symptoms are minute, slightly raised yellow pustules, which later become distinct circles, reddish brown in colour and surrounded by a yellow halo. The disease is spread long distance by wind. Plant to plant spread of the disease is by farm tools, insects or water splash. Severely infected leaves drop off.What to do:

• Destroy crop residues after harvesting.
• Avoid continuous cropping of beans.
• Practise a 2 to 3 year crop rotation without legumes.
• Intercrop with cereals.
• Plant resistant varieties where available (e.g. French bean varieties ‘Theresa’ and “Super Monet”).
• A number of pesticides are available in the market. There are reports claiming that baking soda, compost tea spray, EM (effective microorganisms) and papaya leaf extract control bean rust.