It is an important disease of pea in those areas where cool and moist climate is prevalent during the growing season.


  • All aerial parts of the plants are infected by the disease.
  • Symptoms of leaflets and stipules appear as small water soaked lesions usually developing into large irregular areas (Table-9).
  • Lesions vary in colour, initially being dark green and water soaked, but generally becoming water soaked at the edge and a lighter shade of brown at centre.
  • Under conditions of high moisture, chocolate brown linear streaks are observed on the stem and petiole.
  • Later on, the whole stem turns chocolate brown and is shriveled leading to the death of the plants.
  • Due to infection, immature pods become chocolate brown, thin, twisted and shriveled, lesions are bigger on older pods.
  • Seeds developing in the pods are also discoloured and shriveled.


  • The disease is caused by bacterium Pseudomonas syringae pv. syringae van Hall and P. syringae pv. pisi (Sackett) Young et al.
  • The bacterium is gram -ve, non-spore forming and motile rods with one or more polar flagella.
Disease cycle and epidemiology:
  • The pathogen overwinters in the infected seed.
  • The seed carries the bacterium both externally and internally.
  • It colonizes the intercellular and intracellular spaces of the seed coat but does not penetrate the embryo or cotyledons.
  • Even a very low level of seed infection can cause economic loss, since the disease can spread fast from primary infection foci.
  • The pathogen is carried in irrigation water, splashed by rain or blown in wet winds to other plants and field infection usually occurs through stomata and wounds.
  • Cool, moist weather favours the disease while warm and dry weather retards it.
  • The extent of disease spread depends upon the frequency of rainy periods.
  • If soil is very wet at the time of emergence, it also favours blight transmission from the infected seed to resulting plant.
  • Collect and destroy the infected plant debris.
  • Follow at least three years crop rotation with non leguminous crops.
  • Use disease free seed.
  • Give pre-sowing seed dip treatment in Streptocycline (150 ppm) solution for 90 minutes.
  • With the initiation of the disease, spray the crop with Streptocycline (100 ppm) and repeat at 7 days interval.

  • The symptoms of the disease include chlorotic pattern on the leaves followed by narrowing of leaves coupled with downward rolling and apical malformation.
  • This is followed by vein clearing and production of malformed flowers.
  • The size of pods is reduced which get distorted depending upon disease intensity.
  • Such pods produce infected seeds which are shriveled.
  • The disease is caused by Pea Seed Borne Mosaic Virus which belongs to poty virus (PSbMV) group.
  • The virus particles are filamentous and flexuous rods 770 x 12 nm in size and non-enveloped.
  • The genome consists of single stranded RNA.
Disease cycle and epidemiology:
  • The virus is transmitted mechanically, or by seed or by aphid vectors either semi-persistently or non-persistently.
  • The natural vectors are Acyrthosiphon pisum, Aphis craccivora and A. fabae.
  • The host range of the virus is wide but there are only three significant hosts like pea, lentil and broad bean with regard to economic importance, dissemination through seed.
  • Use resistant pea cultivars.
  • Use reflective mulches to reduce the incidence of this virus.
  • Since seed borne viruses create a within field inoculum source, spray the crop with insecticides like Malathion (0.1%) or Metasystox (0.1%).
Other diseases of importance are:
i. Downy mildew : Peronospora pisi Syd.
ii. Root rot : Aphanomyces euteiches Drechs., Fusarium solani (Mart) Sacc. f. sp. pisi (Jones) Snyd. and Hans.
iii. Leaf spot : Cercospora lathyrina Ell & Ever., C. pisa sativae Stev., Septoria pisi West
iv. Anthracnose : Colletotrichum pisi Pat.
v. Seed and seedling blight : Pythium spp.
Last modified: Friday, 2 March 2012, 6:26 AM