Field Identification
Dark, concentric-ring leaf and fruit spots favored by warm nights and leaf wetness—common on brassicas, carrots, tomatoes, and cucurbits. Severe defoliation exposes fruit to sunburn and ends the season early.
Target-like lesions with fuzzy dark centers; spores are airborne and splash-dispersed. Fruit spots are leathery and sunken. Often follows other leaf damage or senescence.
How to Deal With It
Organic Control Methods
Copper, sulfur, or Bacillus-based biofungicides on a protectant interval through humid weather; remove badly spotted leaves to slow sporulation on small plots.
Trichoderma soil drenches may reduce crown phases on carrots and melons; combine with rotation, not as a solo Hail Mary.
Wider spacing; trellis tomatoes; avoid overhead irrigation; deep crop rotation; destroy infected debris; choose resistant cultivars where they exist.
Plastic mulch reduces soil splash on lower leaves.
Do not save seed from infected fruit; sanitize tunnels between crops; monitor lower leaves after canopy closure.
Let Nature Handle It
Natural Enemies
- Trichoderma spp.
- Bacillus subtilis
- Competitive Saprophytes
Threat Map