Area of impact: Leaves
Description: Watery dark green lesions that develop into round tan or white spots with red or brown margins and sometimes yellow halos. Lesions are most common on the tips of lower leaves and can be 2 mm to 10 mm in diameter.
Pathogen involved: Pseudomonas syringae pv. syringae (a bacterium)
Timing/Conditions: Early in the season during warm wet weather.
Contributing factors: Overwinters in crop debris and infects through plant stomata.
Management practices: Use crop rotation and tillage.