AMSEED American Seed Intelligence Platform
Plant disease

Septoria Leaf Spot

Issue type
disease
Seedborne
No
Resistance code
-
Affects
Tomato

Symptoms

Many small circular spots with dark margins and tan-gray centers peppered across lower leaves, distinguished from early blight by spot size (small and numerous) and tiny black fruiting bodies visible in lesion centers. Defoliates from the bottom up in wet seasons.

Management

Same cultural playbook as early blight, mulch, prune, rotate, water at the base, but with essentially no resistant commercial varieties, sanitation and protectant sprays carry the load in wet-summer regions.

Varieties with documented resistance

VarietyLevelCodeBasisDaysBreeding
Iron Lady tolerant - Independently observed 75-80 F1 hybrid
Jasper tolerant - Breeder declared 60-65 F1 hybrid

This is the page where the difference matters most, because it is where a variety gets chosen for its resistance. Breeder declared means the claim comes from whoever breeds or sells the seed, which for most resistance genes is the only evidence that exists. Independently observed means an institution with no stake in the sale grew the plant and reported what happened.

Sources & References

Evidence: 1 source, an independent reference.

  1. Vegetable MD Online · Cornell University, Plant Pathology, University or Government