This is bean rust (Uromyces phaseoli typica), a fungal disease. Rust can be managaed with: crop rotation, selection of resistant varieties and fungicide applications. Repeated applications are necessary, beginning at the first sign of rust. Contact your local Extension office for fungicide recommendations. Bean rust is very common and associated with cool weather. Working with vines when foliage is wet favors development of fungal diseases. Sanitation, removal, and destruction of "sick" foliage can be helpful. Mulching to retard splashing of soil on foliage when irrigating or raining is also helpful.

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