Seed Treatment
Check with seedsman to determine if seed is hot-water treated. If not, soak seed at 122°F (50°C). Use a 20-minute soak for broccoli, cauliflower, collards, kale, and Chinese cabbage. Soak brussels sprouts and cabbage for 25 minutes. Note. Hot water seed treatment may reduce seed germination. An alternative to hot water seed treatment is to use 1 part Alcide (sodium chlorite), 1 part lactic acid, and 18 parts water as a seed soak. Treat seed for 1 to 2 minutes and rinse for 5 minutes in running water.
Following either treatment above, dry the seed, then dust with captan 50WP or thiram 75WP at 1 level teaspoon for pound of seed. (3 ounces per 100 pounds).
Disease Control
Damping-Off.
Plantbed:Use 0.5 pound of Terraclor 75WP per 100 gallons of solution for control of Rhizoctonia. Apply to the soil at the rate of 100 gallons per 2,000 square feet of bed surface.
Field:Use the following as a banded application after seeding. See label for banded rates based on row spacing. Apply the following in a band up to 7 inches wide:
Ridomil Gold--1-2 pt 4E/a plus
azoxystrobin (Quadris at 0.4-0.8 fl oz 2.08F/1000 ft of row or Amistar at 0.125-0.25 fl oz 80WDG/1000 ft of row labeled only for seedling root or stem rot caused by Rhizoctonia on leafy greens).
Black Rot and Blackleg.
Use hot water seed treatment and resistant varieties. Select site not previously planted to crucifers for seedbeds. Rotate to allow 2 years between cole crop plantings for black rot control and 4 years between cole crop plantings for blackleg control.
For blackleg control in broccoli only, use Rovral 5OWP at 2 pounds per acre applied immediately after thinning as a directed spray to the base of the plant and adjacent soil surface. A second application may be made up to the day of harvest.
For black rot control, fixed copper sprays (1 pound active ingredient per acre) will aid in reducing spread of black rot if treatments are started when disease first becomes evident. A&C #5, Blue Boy, Fortuna, and Super Elite are cabbage varieties with field resistance to black rot.
Bacterial Head Rot.
This soft rot is a problem on broccoli. The varieties Green Defender and Shogun exhibit a reduced level of disease.
Clubroot.
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. Use Terraclor 75WP in one of the following ways. Do NOT use the Terractor 2EC formulation.
I . Use 30 lb/A or 37oz/1000 ft of row. Apply in a 12 to 15-inch band and incorporate 4 to 6 inches deep before planting, or
2. Use 40 lb/A broadcast and incorporate 4 to 6 inches deep before planting, or
3. Use 2 pounds per 100 gallons of solution and 0.5 pint per plant as a transplant solution.
Downy Mildew and Alternaria.
Use one of the following at the first sign of disease and continue every 7 to 10 days (Refer to the pesticide table to determine which fungicide is labelled for each specific cole crop.):
azoxystrobin (Quadris--6.2 - 15.4 oz 2.08F/A or Amistar--2-5 oz 80WDG/A, or
chlorothalonil (Bravo, Echo, Equus)--l.5 pt 6F/A or OLF, or
Cabrio--12-16 oz. 20EG/A, or
Endura--6-9 oz 70WG/A (Alternaria only), or
maneb--l.5-2 lb 8OWP/A or OLF, or
Ridomil Gold Bravo--l.5 lb 76.5WP/A (14-day schedule), or
Switch--11-14 oz 62.5WG/A (Alternaria only)
For downy mildew only, use:
Actigard--1 oz 50WG/A. Begin applications 7-10 days after thinning and reapply every 7 days for a total of 4 applications per season, or
Aliette--3-5 lb 8OWDG/A (14-day schedule)
White Mold
The following biological fungicide has been tested in some states; however, limited information is available on effectiveness in the mid-Atlantic region. Apply 3 to 4 months prior to the onset of disease to allow the active agent to reduce inoculum levels of sclerotia in the soil. Following application, incorporate to a depth of 1 to 2 inches but do not plow before seeding cole crops to avoid untreated sclerotia in lower soil layers from infesting the upper soil layer.
Constans--2-4 lb 5.3WG/A
Alternatively, during the season when soils remain wet for extended periods of time apply preventatively:
Endura--6-9 oz 70WG/A do not make more than two applications per season.
Yellows (Fusarium).
Use resistant varieties. Where resistant varieties are not available, practice long crop rotation intervals.
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.
Where trade names are used no discrimination is intended, and no endorsement by the Cooperative Extension Service is implied.
Dr. Alan A. MacNab, Professor, Plant Pathology
Penn State College of Agricultural Sciences
211 Buckhout Lab, University Park, PA 16802
Updated: Nov, 2005; EMH
Loaded: Nov, 2005; EMH