Ramularia leaf spot (RLS) is caused by the fungus Ramularia beticola.

 

Identification

Symptoms are similar to Cercospora leaf spot. Older leaves are infected first. Light brown round to angular spots (4-7 mm) mature to dark brown, with silvery grey margins turning white upon sporulation. Lesions then become entirely white. Infected leaves turn yellow and die.

 

Ramularia leaf spot of beet.

 

Importance

Occurs only sporadically.

 

Spread

Spores spread via wind and water splash. Mild temperatures and humid conditions favour spore germination.

 

Management

Weather affects RLS severity; warm, dry conditions help crops recover. Dense crops are more susceptible to damage, as are those deficient in sulphur. Fungicides are available.