Vegetables - Disease Management          Pat Donald, MU  (573) 882-2716 
                                         Om Sehgal, MU (573) 882-7060

                               KEY
                          1 = Symptoms
                           2 = Control

BEANS (Dry, Lima and Snap)         

Anthracnose (fungus)   Colletotrichum lindemuthianum 
   1.  Attacks all above-ground plant parts. Small angular lesions
       on leaves and lower veins turn black. Tiny brown spots on  
       pods that later enlarge, turn black with light brown to    
       purplish borders. Mature spots are circular to oval and sunken. 
   2.  Use western grown certified seed to minimize disease. Do not
       work in garden when plants are wet. Use a three-year  rotation. 
       Remove residue after harvest. Lima beans and dry beans only: 
       chlorothalonil (Bravo 500, 720). Dry beans: Maneb 75 or
       Maneb plus Zinc F4.
       
Bacterial blights, Halo Blight or Bacterial Spot (Bacteria)  
Pseudomonas syringae pv. phaseolicola   
   1.  Leaves have irregular watery light green patches.  They turn 
       brown and brittle with yellow borders (halos). Pods have   
       small, water-soaked spots that enlarge to irregular        
       blotches.  Later become brown, dry and sunken areas.    
   2.  Use western grown certified seed. Do not work in garden
       when plants are wet. Spray copper fungicides at weekly
       intervals.  Use fixed copper 50W or Copper hydroxide (Kocide DF).

Common and Fuscous Blight (bacteria)   Xanthomonas spp..   
   1.  Water-soaked or light green areas on leaves. Centers of
       spots become brown, dry and brittle. Pods have water-soaked
       lesion spots that enlarge into broad, irregular blotches.
       Reddish-brown discoloration.  
   2.  Use western grown certified seed. Plow to bury crop residue.
       Clean equipment between fields. Do not work among plants when wet.
       Use treated seed. Use copper-type protectant, such as fixed copper
       or copper hydroxide (Kocide DF).

Downy mildew on lima beans (fungus)   Phytophthora phaseoli   
   1.  Favored by cool, wet weather.  White downy mold on pods,
       causing shriveling and death. Distorted growth on young
       parts. Leaf veins may be purplish and twisted.   
   2.  Use Western grown seed. Plant in well-drained soils. Rotate
       with other crops. Spray fungicide early (just before bloom)
       at weekly intervals, especially in rainy conditions. Use
       chlorothalonil on dry lima only (Bravo 500 2-3 pt./A, 720 1- 
       3/8 pt./A or 90DG) or fixed copper. Metalaxyl (Apron 25W 2 
       oz./cwt.) as a seed treatment is labeled for bean seed.    
       Maneb 80 or Maneb plus Zinc F4.

Powdery mildew (fungus)   Erisiphe polygoni   
   1.  Leaves covered with white powdery growth. Young leaves may
       curl, turn yellow and drop.     
   2.  Use resistant varieties. Consult seed catalogs for current
       information on resistant varieties. Apply a fungicide as
       mildew first appears. Repeat every 7-10 days. Use sulfur
       dust if temperature is less than 80 degrees F. Wettable    
       sulfur (Microthiol special 7 lb./A and Thiolux 3 lb./A).

Rust (fungus)   Uromyces phaseoli   
   1.  Small red to reddish-brown pustules on underside of leaves.
       Sometimes on pods. More serious on pole beans.    
   2.  Use resistant pole bean varieties. Grower should consult
       seed catalogs for current information on resistant         
       varieties. Destroy residues after harvest. Spray or dust   
       plants when rust appears and repeat at seven-day intervals. 
       Use chlorothalonil, (Bravo 500, 720 [lima, blackeye and    
       drybeans only] or 90 DG 2-2 1/2 lb./A), wettable sulfur,   
       sulfur dust, Thiolux 3 lb./A, Maneb 80 or Maneb plus Zinc F4 
       (dry beans only). Do not apply sulfur dust if temperature  
       exceeds 80 degrees F.

Seed decay and damping off  (several fungi)
   1.  Pre-emergence death of seeds.
   2.  Use fungicide treated seed (Ridomil PC 11G for Pythium and Rhizoctonia).

White mold (fungus)   Sclerotinia sclerotiorum 
   1.  Young plants have watery, soft lesions near cotyledonary node.
       Older plants have soft lesions on stems, petioles, leaves or pods.
       White mat-like mycelium develops in older, rotted tissues.   
   2.  Plant in well-drained soils not recently used for beans,
       potatoes, tomatoes, lettuce or cabbage. For snap beans only.
       Apply fungicide 25 percent to 50 percent bloom and repeat at 
       peak bloom. Use benomyl (Benlate WP), thiophanate-methyl   
       (Topsin M 20-30 oz/A), Rovral 1-1/2 lb./A.
 
VIRUSES
Bean Common Mosaic (BV-1) Bean Yellow Mosaic (BV-2) Cucumber Mosaic (CMV)
   1.  Symptoms vary with virus and varieties. Leaves are mottled 
       and puckered with irregular light and dark green areas. Leaves may
       be narrow and strap-like. May have chlorotic spots like halos.
   2.  Use certified seed of resistant varieties, such as Tender green, Top
       crop, Tender crop or Tenderette. Control insect vectors (aphids) with
       approved insecticide, such as malathion or diazinon.