Temperate Pulse Viruses: Bean Yellow Mosaic Virus (BYMV)
Note Number: AG1266
Published: November 2006
Updated: June 2011
Reviewed: June 2013
Bean yellow mosaic virus (BYMV) was first reported on French beans from the USA and the Netherlands in 1925, and is now distributed worldwide. It has a wide host range which includes the temperate pulses and pasture legumes, tropical legumes and ornamental hosts. The virus is spread by a number of aphid species non-persistently as well as being seed and mechanically transmitted.
What to look for
Symptoms of BYMV in the major temperate pulses and pasture legumes are as follows:
- Faba beans develop vein yellowing, followed by obvious green or yellow mosaic vein banding with yellowish line patterns (Figure 1). Symptoms are more prominent on young leaves. Seed symptoms include irregular brownish to blackish staining (Figure 2).
- Symptoms on field peas are variable. The virus may be symptomless or may induce bright mosaic, mottling of leaves and clearance of veins. Necrosis may occur on tips, in stems and veins (Figure 3).
- Desi chickpeas develop apical necrosis, reddening, plant stunting and premature senescence.
- Kabuli chickpeas develop apical necrosis, yellowing, plant stunting and premature senescence.
Lentils develop mild mosaic, light green or yellow leaves. A reduction in leaf size and stunting may occur. Infected plants produce very little seed.
- Narrow-leaf lupins, infected with the necrotic strain of BYMV, initially develop yellow leaves followed by necrosis of growth tips and plant death (Figure 4). Non-necrotic strains of BYMV cause yellowing and dwarfing, but do not cause death of the plant.
- Subterranean clover plants develop leaf mottling, leaf deformation and distinct yellowing between the veins. Plants become dwarfed and symptoms usually occur in patches, and along the edges of paddocks.
BYMV is transmitted by more than 50 aphid species in a non-persistent manner. The main species worldwide are pea aphid (Acyrthosiphon pisum), black bean aphid (Aphis fabae) not found in Australia, cotton aphid (Aphis gossypii), foxglove aphid (Aulacorthum solani), cabbage aphid (Brevicoryne brassicae), green peach aphid (Myzus persicae) and the corn aphid (Rhopalosiphum maidis).
During DEPI surveys in Victoria the following BYMV vectors in pulse crops were detected, blue green aphid (Acyrthosiphon kondoi), cowpea aphid (Aphis craccivora), foxglove aphid (Aulacorthum solani), cabbage aphid (Brevicoryne brassicae) and green peach aphid (Myzus persicae). In Western Australia, the blue green aphid (Acyrthosiphon kondoi), cowpea aphid (Aphis craccivora), green peach aphid (Myzus persicae), dock aphid (Brachycaudus rumexicolens), turnip aphid (Lipaphis pseudobrassicae), corn aphid (Rhopalosiphum maidis), oat aphid (Rhopalosiphum padi), grain aphid (Sitobion miscanthi) and the spotted alfalfa aphid (Therioaphis trifolii forma maculata) have been reported as BYMV vectors (Berlandier et al., 1997).
The virus is also transmitted through seed of most temperate pulses including faba beans, field peas, lentils, and lupins, and through seed of a number of forage legumes and clovers. In Victoria, the DEPI found 18% of lentil seed lots tested had BYMV infections of 0.1-0.9%. In Western Australia, the following BYMV seed transmission is reported: yellow and white lupins 3-6%, field peas 0.3-0.8%, faba beans 0.4%, lathyrus 0.1-0.2% and vetch 0.5% (McKirdy et al., 2000).
Seed transmission of BYMV in medics, clovers and weeds has also been reported in Western Australia as follows, hexham scent (Melilotus indica) (0.5%), burr medic (Medicago polymorpha) (0.9%), barrel medic (Medicago truncatula) (0.3%), hare's foot clover (Trifolium arvense) (0.1%), hop clover (Trifolium campestre ) (0.2%) and cluster clover (Trifolium glomeratum) (0.05%) (McKirdy and Jones 1995).
The host range of BYMV is wide and not limited to Fabaceae. The virus is reported to infect nearly 200 species in 14 families. Temperate pulse hosts include chickpeas, faba beans, field peas, lentils and lupins.Temperate legume pasture hosts include lathyrus, lucerne, vetch, medic and clover species. BYMV has a number of subtropical and tropical pulse hosts, including soybeans, peanuts and French beans as well as legume pasture hosts. It also infects ornamental hosts, the most common being gladiolus species.
In New South Wales a small survey showed that faba bean crops had an average within crop incidence of BYMV of 26% of plants (ranging from 1-63%) (van Leur et al. 2002). Field surveys in Western Australia in 1998-1999 showed that some faba bean and field pea crops were infected with BYMV, and the within crop virus incidences were 31% and 18% respectively (Latham and Jones 2001).
Plot trials in Western Australia showed that lupins infected with the necrotic strain of BYMV can have grain yields reduced by 95% (Cheng and Jones 1999). Seed yield losses recorded on subterranean clover due to infection with BYMV were 58-76% (Jones 1992).
Pulse crop surveys in the last 10 years indicate that BYMV is a minor problem, but in some years the virus levels may be high in lupins, field peas and faba beans in south eastern Australia (Table 1).
Table1: Percentage of pulse crops infected with bean yellow mosaic virus in south eastern Australia and within crop virus incidence
|Virus Survey||Lentil||Faba bean||Field pea||Lupin|
|State/Year||% of sampled crops infected||Within crop virus incidence range %||% of sampled crops infected||Within crop virus incidence range %||% of sampled crops infected||Within crop virus incidence range %||% of sampled crops infected||Within crop virus incidence range %|
|New South Wales|
Note: * = crop not sampled; 0= virus not found.
In 2009, chickpea surveys were conducted in Victoria, South Australia, Southern and Northern NSW. BYMV was not found in any chickpea crop sampled.
Seed is considered to be one of the main sources of BYMV, therefore sowing virus tested seed is recommended and commercial seed tests are available (Seed Health Testing in Pulse Crops AG1250). BYMV causes heavy losses in narrow leafed lupins, so only virus tested seed is recommended for sowing. Virus resistant lupin varieties are now available in Western Australia. BYMV infected pastures are another major source of the virus, which is then spread to crops by aphids.
Chemical control of aphids is not an effective method for controlling non-persistently transmitted viruses such as BYMV. Pulse crops should be sown away from legume pastures to minimise the spread of BYMV. The spread of virus can also be reduced by controlling weed hosts in and around paddocks.
More detailed information can be obtained from the DEPI Information Note Series
Jones RAC (1992). Australian Journal of Agricultural Research 43, 1229-1241.
McKirdy SJ, Jones RAC (1995) Australian Journal of Agricultural Research 46, 135-152.
Berlandier FA, Thackray DJ, Jones RAC, Latham LJ and Cartwright L (1997) Annals of Applied Biology 131, 297-314.
Cheng Y and Jones RAC (1999) Australian Journal of Agricultural Research 50, 589-99.
McKirdy SJ, Jones RAC, Latham LJ and Coutts BA (2000) Australian Journal of Agricultural Research 51, 325-45.Latham LJ, Jones RAC (2001). Australian Journal of Agricultural Research 52, 397-413.
McKirdy et al. (2000). Australian Journal of Agricultural Research 51, 325-345.
Van Leur J, Makkouk K, Freeman A, Schilg M (2002) Proceedings of the 8th International Congress of Plant Pathology, 2-7 February, Christchurch, New Zealand, p265.
Contact/Services available from DEPI
DEPI Field Crops Pathology, Grains Innovation Park, 110 Natimuk Rd, Horsham 3400. Tel (03) 5362 2111, or the DEPI Customer Service Centre 136 186.
This Information Note (AG1266) was originally written by Mohammad and Angela Freeman, Bacteriology & Virology – DPI Horsham, August 2005. It was reviewed by Frank Henry, BioSciences Research - Farm Services Victoria, June 2011. Financial support by the GRDC is gratefully acknowledged.
Published and Authorised by:
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