Necrotic Ringspot

Leaves develop circular dead zones or concentric rings of necrosis from viral infection of the plant tissue throughout the canopy. No cure exists for viral diseases; remove infected plants entirely to prevent further spread to adjacent plants. Use clean planting material from certified virus-free sources for all new plantings.

Remove and destroy symptomatic plants. Do not propagate from plants showing symptoms. Improve drainage around susceptible plants and avoid overwatering. Remove affected material and dispose of it away from the garden. When replanting, choose resistant varieties and amend the soil for better drainage if waterlogging was part of the problem.