Rhizoctonia Disease Management Information

Rhizoctonia Disease Management Information

Causes of Rhizoctonia

  • Caused by a soil borne fungus
  • Spread by any means of infected soil transport
  • Survives in soil for many years
  • Warm to hot temperatures and wet soil favor disease
  • More susceptible crops in rotation including corn, soybeans, and edible beans
  • Many weeds are good hosts for Rhizoctonia including pigweed and lambsquarters
  • Increasing presence of much more virulent strains of Rhizoctonia
  • Very limited use of chemical control options
  • Less wheat and barley in rotation
  • Once infected plants do not recover

Economic Impact

Yields losses can be negligible if few plants are infected. However 50% or more yield loss can occur with severe infestations. Fields with very severe infestations will not be fit for storage and these fields will be abandoned. Rhizoctonia can be found in virtually all fields in the RRV.

Integrated Pest Management is The Key to Rhizoctonia Control Success

Every management option must be utilized to achieve success. American Crystal Sugar Company growers greatly increased utilization of IPM options between 2010 and 2012. Carefully evaluate past options used on your farm and determine where improvement is possible. Your management plan for moderate to severe Rhizoctonia should include:

  • Plant resistant varieties
  • Apply fungicides in a timely manner
  • Provide good field drainage
  • Eliminate row crop cultivation
  • Eliminate rotary hoe use
  • A minimum 3-year rotation is necessary
  • Control susceptible weeds
  • Crop rotation - follow small grain if possible
  • Soil temperature monitoring
  • Seed treatment, in-furrow, or at-plant fungicide use
  • Post-emergence fungicide use

Rhizoctonia Management Options Based on Disease Severity

Disease SeverityRecommended Management
Slight- Use of Kabina seed treatment or Post fungicide use
Moderate- Lengthen crop rotation. Use tolerant variety. Seed treatment, in-furrow or T-band fungicide. One POST fungicide application.
Severe- Lengthen crop rotation. Use tolerant variety. Seed treatment, in-furrow or T-band fungicide. POST fungicide once or twice as needed.

Key Management Considerations

Kabina Use Use

  • Provides early season protection for 4 -5 weeks
  • Widens in-season window for post-emergence fungicide application
  • Can replace in-furrow fungicide applications at planting
  • Easier application at planting

Quadris Use

  • Best post emergence treatment for Rhizoctonia
  • Crop injury risk is high if mixed with liquid fertilizer
  • Compatibility issues exist with liquid fertilizer - constant agitation required
  • Pre-emerge application are not effective
  • Applications on cotyledon and early 2- leaf beets are less effective
  • Will not control infections started before application
  • Don't tank mix with surfactants or organosilicates, COC, MSO, or EC based pesticides
  • Can be successfully mixed with glyphosate
  • Will give excellent in-furrow results until mid to late July
  • Apply it exactly between successive microrate applications
  • 4-6 leaf beet stage is ideal application timing
  • Better to apply to early than too late
  • Quadris gave good to excellent results in 75-80% of treated fields in 2010
  • About 246,000 acres were treated with Quadris in 2013

Headline Use

  • Tank mixes with Redline, Soygreen or 10-34-0 require constant agitation
  • Spray out all tank mixes within 4 hours
  • If the tank mix sits overnight agitate very thoroughly before use
  • Adding at least 1 gpa of water to 10-34-0 greatly improves compatibility
  • Headline will give only fair to good post emergence Rhizoctonia control
  • In-furrow treatments give about 4-6 weeks of protection
  • Occasional stand loss can occur with in-furrow applications
  • Consider using injection system equipment to apply it with starter fertilizer

Proline Use

  • Proline with surfactant has provided very good control when applied post emergence in a timely manner

Key Components to Successful Use of Headline and Quadris in-furrow

  • The better the agitation the less frequently problems will occur
  • Premixing the fungicides with water and then adding to starter fertilizer will reduce compatibility issues
  • The longer fungicide and starter remains tank mixed the greater are the chances of product separation and nozzle plugging
  • Quality of the starter fertilizer product may cause greatly varying mixing results
  • Water and starter fertilizer temperature, air temperature, nozzle or orifice size, and sprayer screen size may all effect compatibility or nozzle plugging
  • Using injection systems to put fungicide into the starter fertilizer just ahead of application will significantly reduce or eliminate compatibility issues

The single most critical Rhizoctonia management strategy after variety selection is applying a post emergence application of Quadris at the correct timing.

Ag Staff has the Info:

Contact your agriculturist for a much more comprehensive list of best management practices for in-furrow and POST application of Headline & Quadris for Rhizoctonia control.