Scab of Radish

Disease Information

Scab
Streptomyces scabies (Bacteria)

Symptoms

Brown-yellow circular lesions on roots; sunken, cracked lesions which may be irregular in shape and coalesce

Comments on disease

Disease also occurs in potato, turnip and rutababga

Management

Management of scab can be very difficult; rotate crops to non-host for four years; maintain a high level of soil moisture; avoid increasing soil pH through soil amendments.

Chemical Control

 There is occasional use of azoxystrobin to treat white rust and mefenoxam to treat downy mildew outbreaks. . copper hydroxide, phosphoric acid compounds, pyraclostrobin, and sulfur. Fludioxonil is available as a seed treatment.

 Cultural Control

 Most of the cultural control provided to the radish crop comes in the form of proper field preparation and seed selection. Field varieties usually have some amount of disease resistance. By short-fallow and discing, soil fumigants are not required, and proper drainage alleviates root rot and other fungal problems.

 

 



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