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Rust - Beans

Uromyces fabae

Pathogen

Fungus

Hosts

Beans (field, broad)

Symptoms

Brown / black pustules of rust with chlorotic halos are typically found on leaves.

Development

The trash-borne fungus can infect autumn sown bean crops or can survive throughout the winter on old bean straw and infect spring sown crops. The characteristic brown / black pustules produce wind-blown spores, which then spread the disease throughout the surrounding and neighbouring crops.

Favourable Factors

Warm, dry weather and low potassium soils.

Importance

The disease usually develops too late to seriously affect the yield of winter bean crops, but can occasionally damage and reduce the yield of spring crops.

Control

  • There are no resistant varieties.

  • Maintain a potassium soil index of at least two.

  • Remove crop debris after harvest.

  • Remove infected volunteers.

  • Many of the foliar fungicides applied to control chocolate spot will give some suppression of bean rust, but if conditions favour disease development a specific fungicide with activity on rust can be applied with a repeat application 2 – 3 weeks later if required.