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Angular leaf spot

Pseudomonas syringae pv. lachrymans

1 host plant

Last updated

Data Coverage 3 of 6 dimensions
Causal Agent
Host Plants
Symptoms
Management
GDD Threshold
Regional Notes

Water-soaked lesions with angular margins develop on leaves along veins. This bacterial disease spreads by rain splash. Avoid overhead watering and space plants.

Leaf spot and blotch diseases are primarily cosmetic on established plants, though repeated years of heavy infection can weaken them. Rake up and remove fallen leaves to reduce the spore load going into the next season. Avoid overhead watering that splashes spores from the ground onto lower leaves. If the problem is severe, protective fungicide sprays during spring leaf emergence can help, but sanitation does more than chemistry for most leaf spots.

Quick Reference

Causal Agent
Pseudomonas syringae pv. lachrymans
Host Plants
1
Favorable Conditions
Cool to moderate temperatures (below 72°F/22°C), high humidity (>95%), prolon...

Management

What Triggers Infection

Cool to moderate temperatures (below 72°F/22°C), high humidity (>95%), prolonged leaf wetness, overhead irrigation, early-season conditions

Cultural Controls

  • Plant disease-free seed.
  • Do not plant cucumber or related crops in the same location for at least two years.
  • Plant resistant varieties.
  • Resistant varieties may still become infected, but will suffer less damage.
  • Pickling varieties: 'Calypso, 'Cross Country', 'Express', 'Frontier', 'Pioneer', 'Regal', 'Royal'.
  • Slicing varieties: 'Bel Aire', 'Dasher II', 'Encore' Avoid overhead watering.

Host Plants (1)