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Broad Bean Rust


Broad Bean Rust

Usually appear in

Summer to Autumn

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Caused By:-     The Fungus Uromyces viciae-fabae


Broad Bean rust which is caused by the fungus Uromyces viciae-fabae and infects Vicia beans which include Bell Bean or Tic Bean, Broad Bean, Fava Bean, Field Bean. This fungus is unrelated to rust on the Phaseolus Genus of beans which include beans Bush bean, French bean, Kidney bean, Pinto bean, Pole bean, Runner bean, Snap bean which is caused by the fungus Uromyces appendiculatus. Rust fungi are described as biotrophs which means that they grow within the living tissues of the plant and extract nutrients from the cells. Although they do not kill the tissues rapidly – heavy attacks by rusts can cause tissues to collapse and die prematurely.
Most rusts require two different plant hosts in order to complete their life cycle, but both on bean seem to only have a single host.
It is not as damaging as another common broad bean disease, chocolate spot, but severe attacks can cause defoliation. Expect to see significant levels of this rust from mid-summer.
It attacks broad beans, peas and other related legumes and has several races, but in the UK is only important on broad beans. Runner and French beans are affected by a more serious, but unrelated rust disease.
This disease occurs occasionally under prolonged periods of warm, moist weather and exists in many pathotypes which attack related species.
The fungus causes small, dusty dark brown spots which covers leaves and stems.
Later, dark brown resting spores form on the underside of leaves which survive between crop cycles to infect new crops.
It usually it develops too late to affect the yield of early sown beans, but late-sown spring beans can suffer badly in July, when the warm days and humid nights favour the disease.
Severely infected leaves whither and die and cropping is reduced. The pods and stems can also be affected.
Picture from Wikimedia Commons.
See also these other rusts Anemone, Antirrhinum, Bluebell, Cedar Quince, Chrysanthemum White, Fucshia, Gladiolus, Gooseberry, Hollyhock, Juniper Pear, Mahonia, Mint, Pear Juniper, Pelargonium, Periwinkle, Plum, Potato Internal, Quince, Rhododendron, Rose, Rust, White.


As with any fungal disease one of the best ways of preventing it is by good hygiene. Remove all dead leaves in autumn to prevent the spores from over wintering. If the leaves is from an infected plant burn them.
Check plants regularly and remove infected leaves by hand as soon as they are seen and then spray with a suitable fungicide. Spray the plant and the soil around it with a fungicide suitable for the control of rust fungus.
Water the compost of susceptible plants directly trying not to wet the foliage as the rust needs a period of leaf wetness to germinate and infect.
Maintain an open structure to allow good air circulation through the plant and ensure greenhouses are always well ventilated.
Rotate bean with non-host crops.
Disinfect reusable poles in bean production.
Often there are resistant varieties of the plant you wish to grow.
Avoid over application of nitrogen, which produces soft growth which is more susceptible and ensure adequate potassium fertilisation.

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