Uromyces viciae-fabae var. viciae-fabae
Encyclopedia
Uromyces viciae-fabae var. viciae-fabae is a plant pathogen commonly known as Faba-bean rust. It is a leaf and stem rust of beans and causes partial defoliation, a reduction in photosynthetic
leaf surface and a reduction in yield.
This rust fungus
occurs on both cultivated and wild plants of Vicia
, Lathyrus
, Pisum
and Lens
. It is autoecious
, completing its life cycle on one plant host and macrocyclic
, producing five types of spores during its life cycle.
are mostly on abaxial leaf surfaces.
The aecia
are mostly on abaxial surfaces in small groups, mostly near the veins, the peridium is cupulate and whitish with spores 18–26 by 15–21 µm, broadly ellipsoid and verrucose.
The uredinia
are amphigenous and yellowish-brown with spores 24–29 by 19–22 µm, broadly ellipsoid, pale golden and uniformly echinulate, normally with four pores, either equatorial or variously distributed and with small caps.
The telia
are sometimes on the adaxial surfaces or sometimes amphigenous and on stems, exposed, blackish brown and compact with spores 27–35 by 19–23 µm, oval or obovoid, smooth and chestnut brown, the pedicels brownish and about 60 µm long.
, yield reductions of over 50% have occurred. Control measures include the use of resistant varieties of bean and the strategic use of foliar fungicides, which need to be applied before heavy infections occur to minimise crop losses.
Photosynthesis
Photosynthesis is a chemical process that converts carbon dioxide into organic compounds, especially sugars, using the energy from sunlight. Photosynthesis occurs in plants, algae, and many species of bacteria, but not in archaea. Photosynthetic organisms are called photoautotrophs, since they can...
leaf surface and a reduction in yield.
This rust fungus
Rust (fungus)
Rusts are plant diseases caused by pathogenic fungi of the order Pucciniales. About 7800 species are known. Rusts can affect a variety of plants; leaves, stems, fruits and seeds. Rust is most commonly seen as coloured powder, composed off tiny aeciospores which land on vegetation producing...
occurs on both cultivated and wild plants of Vicia
Vicia
Vicia is a genus of about 140 species of flowering plants commonly known as vetches. It is in the legume family . Member species are native to Europe, North America, South America, Asia and Africa. Some other genera of their subfamily Faboideae also have names containing "vetch", for example the...
, Lathyrus
Lathyrus
Lathyrus is a genus of flowering plant species known as sweet peas and vetchlings. Lathyrus is in the legume family Fabaceae and contains approximately 160 species. They are native to temperate areas, with a breakdown of 52 species in Europe, 30 species in North America, 78 in Asia, 24 in...
, Pisum
Pisum
Pisum is a genus of the family Fabaceae, native to southwest Asia and northeast Africa. It contains one to five species, depending on taxonomic interpretation; the International Legume Database accepts three species, one with two subspecies :...
and Lens
Lens (genus)
The genus Lens of the legume family Fabaceae contains four species of small, erect or climbing herbs with pinnate leaves and small inconspicuous white flowers and small flattened pods...
. It is autoecious
Rust (fungus)
Rusts are plant diseases caused by pathogenic fungi of the order Pucciniales. About 7800 species are known. Rusts can affect a variety of plants; leaves, stems, fruits and seeds. Rust is most commonly seen as coloured powder, composed off tiny aeciospores which land on vegetation producing...
, completing its life cycle on one plant host and macrocyclic
Rust (fungus)
Rusts are plant diseases caused by pathogenic fungi of the order Pucciniales. About 7800 species are known. Rusts can affect a variety of plants; leaves, stems, fruits and seeds. Rust is most commonly seen as coloured powder, composed off tiny aeciospores which land on vegetation producing...
, producing five types of spores during its life cycle.
Description
The spermogoniaRust (fungus)
Rusts are plant diseases caused by pathogenic fungi of the order Pucciniales. About 7800 species are known. Rusts can affect a variety of plants; leaves, stems, fruits and seeds. Rust is most commonly seen as coloured powder, composed off tiny aeciospores which land on vegetation producing...
are mostly on abaxial leaf surfaces.
The aecia
Rust (fungus)
Rusts are plant diseases caused by pathogenic fungi of the order Pucciniales. About 7800 species are known. Rusts can affect a variety of plants; leaves, stems, fruits and seeds. Rust is most commonly seen as coloured powder, composed off tiny aeciospores which land on vegetation producing...
are mostly on abaxial surfaces in small groups, mostly near the veins, the peridium is cupulate and whitish with spores 18–26 by 15–21 µm, broadly ellipsoid and verrucose.
The uredinia
Rust (fungus)
Rusts are plant diseases caused by pathogenic fungi of the order Pucciniales. About 7800 species are known. Rusts can affect a variety of plants; leaves, stems, fruits and seeds. Rust is most commonly seen as coloured powder, composed off tiny aeciospores which land on vegetation producing...
are amphigenous and yellowish-brown with spores 24–29 by 19–22 µm, broadly ellipsoid, pale golden and uniformly echinulate, normally with four pores, either equatorial or variously distributed and with small caps.
The telia
Rust (fungus)
Rusts are plant diseases caused by pathogenic fungi of the order Pucciniales. About 7800 species are known. Rusts can affect a variety of plants; leaves, stems, fruits and seeds. Rust is most commonly seen as coloured powder, composed off tiny aeciospores which land on vegetation producing...
are sometimes on the adaxial surfaces or sometimes amphigenous and on stems, exposed, blackish brown and compact with spores 27–35 by 19–23 µm, oval or obovoid, smooth and chestnut brown, the pedicels brownish and about 60 µm long.
Life cycle
The telia survive in a semi-dormant state in crop residues both in the field and on seed. The teliospores they produce are blown by the wind and come to rest on volunteer plants and seedlings, infecting them. Aecia are produced and liberate aeciospores which spread the infection within the crop and to other nearby bean crops. Uridinia are produced on the stems and leaves and liberate urdiniospores which spread the rust throughout the crop canopy. Late in the season, telia form on stems and leaves and remain in crop debris after harvest ready to infect next season's crop.Damage and control
When faba-bean rust is present, leaves of infected plants exhibit many small, orange-brown pustules, each surrounded by a pale yellow halo. Severely infected leaves wither and may drop from the plant. Larger pustules occur on the stems and isolated pustules may be found on the pods. Severe infection may result in reduced seed size and may cause yield losses of up to 30%, while in combination with chocolate spotBotrytis fabae
Botrytis fabae is a plant pathogen, a fungus that causes chocolate spot disease of broad or fava bean plants, Vicia faba.-Symptoms:...
, yield reductions of over 50% have occurred. Control measures include the use of resistant varieties of bean and the strategic use of foliar fungicides, which need to be applied before heavy infections occur to minimise crop losses.