Streptomyces scabies (Bacteria)
circular lesions on roots; sunken, cracked lesions which may be irregular in
shape and coalesce
Comments on disease
occurs in potato, turnip and rutababga
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.
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.
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.