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Ministry of Agriculture, Food and Rural Affairs

Pseudomonas Bacterial Spot

Pseudomonas bacterial spot Pseudomonas bacterial spot Pseudomonas bacterial spot
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Beginner

Scientific Name 
Pseudomonas syringae pv. syringae

Identification

  • This pathogen can cause severe spots and yellowing on pepper foliage
  • Although symptoms can initially look very severe, once conditions become less favourable for the pathogen new growth is unaffected
  • Not known to cause fruit lesions or have an economic impact

Often Confused With
Bacterial spot (Xanthomonas campestris)

Period of Activity
Pseudomonas syringae prefers temperatures of 16- 24°C (61- 75°F) and high humidity.

Scouting Notes
Look for irregular dark lesions and yellowing on pepper foliage.  Check for fruit lesions.  Pseudomonas is not known to cause fruit lesions on pepper, while Xanthomonas may cause scabby fruit lesions.  Laboratory diagnosis may be necessary to distinguish this disease from bacterial spot (Xanthomonas campestris).

Thresholds
None established.

Advanced

Scientific Name
Pseudomonas syringae pv. syringae

Identification
This pathogen can cause severe spots and yellowing on pepper foliage.  Little information is available about this disease, but it has not been known to cause fruit lesions or have an economic impact.  Although symptoms can initially look very severe, once conditions become less favourable for the pathogen, new growth is unaffected. 

Often Confused With
Bacterial spot (Xanthomonas campestris)

Biology
This disease is caused by a bacterial pathogen which can also infect tomato.

Period of Activity
Pseudomonas syringae  prefers temperatures of 16- 24°C (61- 75°F) and high humidity.  Leaf wetness encourages disease development.

Scouting Notes
If dark, necrotic lesions and yellowing are seen on foliage, check for fruit lesions.  Pseudomonas is not known to cause fruit lesions on pepper, while Xanthomonas may cause scabby fruit lesions.  Otherwise, laboratory diagnosis may be necessary to distinguish this disease from bacterial spot (Xanthomonas campestris).  Xanthomonas prefers warmer temperatures than Pseudomonas.

Thresholds
None established.

Management Notes

  • The pathogen spreads through splashing water.
  • Overhead irrigation may help the disease to develop and spread.