Seed testing for bacterial blight is available from: Bacteria can remain viable on seed for at least 2 years. A field inspection should occur at mid to late pod fill. The use of clean seed will minimise the possibility of disease, provided the land has not been cropped to peas for several years.ĭo not use seed from crops found to have bacterial blight during field inspections. The use of disease free seed is the main control measure recommended. syringae.įor further information on disease ratings refer to the Victorian Pulse Disease Guide. pisi, but the frequency of bacterial blight can be reduced by avoiding varieties most susceptible to Pseudomonas syringae pv. All local varieties are susceptible to Pseudomonas syringae pv. Managementīacterial blight can be avoided by using an integrated approach to management that encompasses:įield pea varieties vary in their susceptibility to bacterial blight. The disease can restrict exports as some countries will only import field pea seed from regions where bacterial blight does not occur. Severe epidemics can result in crop failure but losses are usually less than 20%. Economic importanceīacterial blight is widespread in field peas in Victoria but its severity varies greatly from crop to crop and between seasons. Rainfall, heavy dews, strong winds and cold temperatures provide the most favourable conditions for spread of disease within crops. Plants damaged by frosts or any other physical damage are more susceptible to infection. Infection may occur at any stage of plant growth and is most prevalent following frosts. During wet weather, bacteria spread from infected to healthy plants by rain-splash, wind-borne water droplets and plant to plant contact. The disease commonly becomes established within a field by sowing infected seed. syringae can survive on a variety of host plants. Disease cycleīoth bacteria can survive on seed or pea trash, whilst P. syringae are indistinguishable from each other on the pea plant. The symptoms of bacterial blight caused by Pseudomonas syringae pv. Heavily infected seed may be discoloured, but light infection has no visible effect on seed. Pre-emergence and post-emergence damping-off may occur, and even advanced plants may be killed. Stem infection may spread upwards to the stipules and leaflets. Stem lesions may coalesce, causing the stem to shrivel and die. These begin as water-soaked areas, which later turn olive-green to dark brown. Lesions may also develop on stems near ground level. The lesions on the leaflets turn yellowish and later brown and papery, lesions on the pods are sunken and turn olive-brown. The lesions may enlarge and coalesce, but are always delimited by the veins and develop a characteristic fan shape. The disease first becomes evident as small, dark-green, water-soaked lesions on leaves and stipules. It can be controlled by crop rotation, time of sowing, farm hygiene, sowing disease free seed and using resistant varieties. Temperate pulse viruses: subterranean clover stunt virusīacterial blight is a serious disease of field peas that is caused by the pathogens Pseudomonas syringae pv. Temperate pulse viruses: pea seed-borne mosaic virus Temperate pulse viruses: bean yellow mosaic virus Temperate pulse viruses: bean leafroll virus Temperate pulse viruses: cucumber mosaic virus
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