Vegetables - Disease Management          Pat Donald, MU  (573) 882-2716 
                                         Om Sehgal, MU (573) 882-7060
                                
                               KEY
                          1 = Symptoms
                           2 = Control

CRUCIFERS (Broccoli, Brussels sprout, Cabbage, Cauliflower, Collards,
           Kale, Turnips)      

Black leg (fungus)   Phoma lingam   
   1.  Dark, sunken, circular to oval or irregular areas on stems
       & leaves. Black dots develop in areas. Stems may be girdled
       near ground line, causing wilting & death of plants. Wilted
       leaves tend to stay on affected plants, rather than fall off.
   2.  Use Western grown, disease-free seed. Use disease-free     
       plants as transplants in disease-free soil. Unless already
       treated, use hot water seed treatment (immerse cheesecloth
       bag of seed in 122 degrees F for 25 minutes for cabbage. 
       All other seed 20 minutes). Remove diseased plants. Use    
       4-year crop rotation free of crucifers. Apply fungicide as
       directed spray to base of plants after thinning (2-4 leaf
       stage).  Use iprodione (Rovral 2 lb./A) for broccoli only.

Black rot or blight (bacterial)   Xanthomonas campestris   
   1.  Leaf infections yellow with V-shaped pattern. Dwarfed or
       one-sided plants with yellow to brown leaves. Vascular rings
       in stem and leaf veins turn black. Head may decay and drop. 
   2.  Use care in selecting disease-free seed & plants. Follow
       same measures as for Black leg. Control insects.

Club root (fungus)   Plasmodiophora brassicae 
   1.  Stunted, sickly plants that wilt readily. Roots malformed
       and enlarged (Club root not prevalent in Missouri).     
   2.  Follow measures under Black leg. Apply fresh hydrated lime,
       10 lbs per 100 square foot & work into top soil two to four
       weeks before planting. Use Terraclor (PCNB) in transplant
       water. Apply 15 lbs./1000 feet of row at transplant time.

Downy mildew (fungus)   Pseudoperonospora cubensis    
   1.  White downy mold on underside of leaves.  Leaves later turn
       yellow, shrivel, turn brown and die. Infected tissues become
       brown and parchment-like. Cabbage heads may have dark- brown
       sunken spots on outer leaves. Cauliflower curds may have
       blackened spots.    
   2.  Begin fungicide applications when diseases become apparent.
       Continue at weekly intervals. Shorten intervals to 3-5 days
       under severe conditions. Use chlorothalonil (Bravo 500 2 1/4
       pt./A, 720 1 1/2 pt./A, 90 DG 1 1/2 lb./A), Maneb 80 1 1/4
       lb./A, Maneb + Zinc F4 1.2 qt./A, Alietti WDG 2-5 lb./A, or
       Ridomil/Bravo 81W 1 1/2 lb./A.  Do not apply later than 7
       days before harvest (10 days on kale).

Root knot nematode    Meloidogyne spp.
   1.  Galls or knots on roots.  Possible wilting of foliage during
       sunny days.  Unthrifty plant appearance.
   2.  Rotate to non-host crops, move garden site or solarize soil. 
       Commercial growers may use Mocap EC at 3 1/2 quarts per acre
       or Mocap 10G at 50 pounds per acre broadcast.

Yellows or Fusarium wilt (fungus)   Fusarium oxysporum f. sp. conglutinans
   1.  Plants often stunted, yellow-green & one-sided. Lower portion of
       leaf blade near petiole or midrib wilts & dies first.  Lower leaves
       drop off, resulting in bare stems and small heads. Stems have
       darkened rings inside. Does not cause head rot. 
   2.  Rotate ground for crucifer crops if yellows becomes a
       problem. Grow yellows-resistant varieties. Consult seed
       catalogs for current information on resistant varieties.