Rust - Beans
Severe disease pressure & close up of rust
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.
Severe disease pressure
Close up
