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BEAN RUST- FUNGICIDE DECISION STRATEGY
See Bean Pesticide Summary for pesticide details
Colorado State University Integrated Pest Management Program
CHECKLIST FOR APPLICATION  Your Score
Current Season Rainfall, Dew, Humidity from Planting to V - 4 Stage   
Above Normal: 2  Normal: 1 Below Normal: 0
Current Season Temperature from Planting to V - 4 Stage   
Below Normal: 2  Normal: 1 Above Normal: 0
Forecasted Rainfall, Dew, Humidity Between V - 4 and R - 4 Stages   
Above Normal: 2  Normal: 1 Below Normal: 0
Forecasted Temperature Between V - 4 and R - 4 Stages   
Below Normal: 2  Normal: 1 Above Normal: 0
Bean Rotation less than 3 years and/or Volunteer Beans Within 2 Miles from Field   
Yes: 4  Unknown: 2 No: 0
Variety Reaction to Rust Races in the Region   
Susceptible: 4  Unknown: 2 Resistant: 0
Initial Rust Pustules Confirmed on Numerous Plants Prior to R1 (Early Flower)   
Yes: 4  No: 0
Initial Rust Pustules Confirmed on Numerous Plants Prior to R4 (Mid Pod Set)   
Yes: 2  No: 0
Total Score:  

ENVIRONMENTAL THRESHOLDS (weekly) for Disease Forecast:
Temperature: Normal = average high temperature of 86 F
Moisture: Normal = 0.25 inches of rainfall
DISEASE RISK SUMMARY - If the Total Score was:

more than 15 = High Risk 10 - 15 = Moderate Risk less than 10 = Low Risk
If the variety is susceptible and the total score was 10 or higher, treatment with a labeled fungicide such as Maneb/Manex (30 day preharvest interval), Bravo/Terranil (14 day phi), Endura (21 day phi), Headline or Quadris (30 day phi), should be considered at first confirmed signs of rust (often the R1 to R3 stage) on numerous plants in the field or nearby region. Follow a 5 to 10 day interval between sprays, depending upon disease pressure and the fungicide selected until 14 to 30 days phi or the R7 growth stage is reached, whichever occurs first.
Note: As with any pesticide, always read and follow instructions and precautions. Refer to the Dry Bean Growth Stage Chart, and incorporate other Integrated Pest Management approaches such as crop rotation, sanitation, certified seed, plant resistance, tillage, moderate irrigation and fertility, and timely scouting.
[Checklist adapted for Colorado and surrounding region by Dr. H. F. Schwartz, M. S. McMillan, and K. L. Otto, 6/98]

Common Rust - IPM STATEGY for Edible Bean (dry, snap, seed):

  • Rotate to exclude susceptible host crops (i.e., sunflower, soybean, canola, pea) for 3 + years; examples of non-host crops are small grains and corn
  • avoid planting in fields with a history of disease during the last 3 - 5 years
  • plant resistant or less susceptible varieties if available
  • follow recommended plant population - row & plant spacing
  • soil test and use a moderate fertility program; e.g., not to exceed 75 - 100 lb N/A
  • incorporate fall and/or spring tillage to eliminate carryover seed and volunteer beans in last year's bean fields, promote root health and moisture drainage in this year's bean fields
  • monitor irrigation scheduling to avoid flowering-period deficiency but late-season saturation
  • utilize timely scouting, disease forecasting, and weather monitoring services
  • when justified, use timely applications of recommended fungicides at first signs of disease; maintain protection throughout flowering and early pod set