Common Rust: Symptoms, Management & Resistant Varieties

Symptoms

Cinnamon-brown powdery pustules erupting through both leaf surfaces, oval and scattered rather than banded. Severe infection on susceptible sweet corn can strip photosynthetic area before the ear fills.

Management

Resistance is the practical control in sweet corn, where the crop is short-season and fungicide timing is awkward. Reaction is race-specific: single Rp genes confer near-immunity to some rust races and none at all to others, so a variety rated resistant in one region can fail in another once a virulent race arrives.

Varieties with documented resistance

Variety	Code	Basis	Days	Breeding
Silver Queen	-	Independently observed	-	F1 hybrid
Ambrosia	-	Independently observed	-	F1 hybrid
Argent	-	Independently observed	-	F1 hybrid
Incredible	-	Independently observed	-	F1 hybrid
Bodacious	-	Independently observed	-	F1 hybrid
Kandy Korn EH	-	Independently observed	-	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.

Relative Resistance of Sweet Corn Varieties to Common Diseases in the Northeast · University of Connecticut Extension (2014), University or Government