Commercial Disease Controls
The Pennsylvania State University
Cooperative Extension

Radishes, Rutabagas, and Turnips

Seed Treatment

Soak seed in hot water at 122degF (50degC). Soak rutabagas for 20 minutes and turnips for 25 minutes. Dry, then dust with captan 50WP or thiram 75WP at 1 level teaspoon per pound of seed.

Disease Control

Damping-Off
Add the following preplant incorporated or as a soil surface spray after planting:

Ridomil Gold -- 1-2 pt 4E/A

Black Rot, Blackleg, Alternaria
Use hot water seed treatment. See the preceding "Seed Treatment" section.

Clubroot
Radishes are susceptible to clubroot, though turnips are resistant. Of the radish varieties, Champion is quite susceptible. Use of irrigation water containing spores of the fungus is one of the principal ways the disease is spread to new fields. If clubroot occurs, take care to clean and disinfest any equipment to be used in other fields to prevent spread. Adjust soil pH with hydrated lime to as close to 7 as possible. Improve the drainage in the field by making ditches, etc., and grow the crop on raised beds.

Downy Mildew
Apply the following when the disease is first noticed and repeat every 7 to 10 days:

copper, fixed -- l-2 lb 61DF/A or OLF

Leaf Spots
Alternate the following every 7 to 10 days when the disease is first noticed:

azoxystrobin (Quadris--6.2 - 15.4 oz 2.08F/A or Amistar--2-5 oz 80WDG/A), or

Cabrio--8-12 oz 20EG/a,

with

copper, fixed--1-2 lb 61 DF/A or OLF

Scab
This disease is more severe under dry soil conditions, high soil pH, and low level of magnesium. Heavy irrigation in the first 2 weeks after emergence and the application of sulfur to reduce soil pH will assist in disease control.

White Rust
At the first sign of disease in fields, alternate the following every 7 days:

azoxystrobin (Quadris--6.2 - 15.4 oz 2.08F/A or Amistar--2-5 oz 80WDG/A) or
Cabrio--8-12 oz 20EG/A, with
Ridomil Gold/Copper -- 2 lb 7OWP/A

Note: Where trade names are used, no discrimination is intended and no endorsement by the Cooperative Extension Service is implied. Information provided is intended for consideration by the user, but is not intended to be a recommendation. Production decisions should be based on consideration of many types of information (scientific, experiential, economic, legal, etc.) available to the user.