Chemical Control: Application of Fungicides

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Chemical Control Application of Fungicides
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General Fungicide Application Methods

• Air
• Chemigation
• Ground
• In furrow (wont be discussed today)
• Seed (wont be discussed today)

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Columbia Basin Potatoestest crop
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How Good Are These Methods for Applying Fungicide?
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Infra red photo showing late blight infection due
to poor aerial application
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Infra red photo showing late blight infection due
to poor chemigation application
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Late blight infection due to a poor ground
application
G. A. Secor
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Air Application
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Factors that Contribute to Application Efficacy
Using Air

• Wind
• Nozzle type
• Pressure
• Droplet size (need most gt100um)
• Water volume
• Obstructions
• Speed
• Density of plant canopy
• Effective swath width

• Humidity
• Wind Shear
• Drift
• Type of air craft
• Topography
• Lack of skips
• Distance to canopy
• Cost
• Initial coverage
• Initial concentration
• Redistribution

(Jacobsen 1986. Calibration and use of aircraft
for applying fungicides in Methods for
evaluating pesticides for control of plant
pathogens)
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Chemigation
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Factors that Contribute to Application Efficacy
Using Chemigation

• Wind
• Amount of water
• Speed
• Expense
• Potential for Skips
• Initial Fungicide Concentration
• Initial Coverage
• Redistribution

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Ground Application
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Factors that Contribute to Application Efficacy
Using Ground

• Type of Equipment
• air assist, conventional, electrostatic
• Nozzles
• extended flat fan, hollow disc cone, many others
• Amount of Water
• Dew Spread
• Pressure

• Speed
• Expense
• Wind
• Initial Coverage
• Initial Fungicide Concentration
• Redistribution

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Comparison of These Application Methods
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Hamm Clough 1999
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Hamm Clough 1999
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Comparison of Application Methods
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Comparing Water Amount Used During Air Application
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Hamm Clough 1999
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Improving Chemigation
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Geary et al. 1999
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Correct Water Amount to Use During Ground
Application
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Stripe Rust on Kentucky Blue Grass
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AUDPC
Ground Application
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Alternating Air with Chemigation, A Cost
Effective Alternative to Using Only Air
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Late Blight on Potato
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Hamm et al.
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The Importance of Timing
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Application Timing Critical for Disease Control
Hamm 1995
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Selected References

• Hamm et al. Plant Dis. 1999. 83 441-44
• Geary et al. Plant Dis. 1999. 83 512-515
• Jacobsen BJ. 1986. Methods of calibration and
  use of aircraft for applying fungicides. in 2nd
  Edition, Methods for Evaluating Plant Fungicides,
  Nematicides, and Bacteria. K. D. Hickey, Ed.
  American Phytopathological Society, St. Paul, MN.
  p. 39-44.
• Geary et al. 2004. AJPR 81305-316.
• Hamm et al. 2008. Applying Pesticides. In, Potato
  Health Management, 2nd edition. APS Press.

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Residue--Stems Verses Leaves
Day of Application
7 Days After
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Hamm et al
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In furrow
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Nozzle