Application Techniques

1
Application Techniques

• Chris Boerboom
• Extension Weed Scientist
• University of Wisconsin

2
Application Goal

• 1. Place fungicide as deep into the canopy as
  possible
• 2. Protectants require maximum coverage of
  soybean leaf surface
• Canopy penetration
• Small droplets -
• better coverage, but cannot be forced into the
  canopy
• Larger droplets -
• less coverage, but penetrate canopy better

3
Application Goal

• Complete spray coverage is important
• Different than postemergence herbicide
  applications
• Changes to nozzles, volume, and pressure

4
Nozzle types for fungicides

• Pressure Rating
• XR TeeJet (flat fan) gt 30 psi Excellent
• XR TeeJet (flat fan) lt 30 psi Good
• TwinJet Excellent
• Turbo TeeJet gt 30 psi Very good
• Turbo TeeJet lt 30 psi Good
• Standard flat fan Good
• Air induction Good
• Hollow disc-cone (banding nozzle) Good

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Nozzle types

• XR TeeJet flat fan TwinJet
• Turbo TeeJet

Excellent spray distribution over a wide range of
pressures 15-60 PSI Reduces drift at lower
pressures, better coverage at higher pressures
Penetrates crop residue or dense foliage Smaller
droplets for thorough spray converge Spray
pressure 30-60 PSI
110o flat spray pattern Larger droplets for less
drift Spray pressure 15-90 PSI
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Nozzle types

• Air induction Hollow disc-cone

Excellent wear life - ideal for abrasive spray
materials. Produce smaller droplets for thorough
coverage. Spray pressure 40-300 PSI
Larger droplets for less drift - large,
air-filled drops through the use of a venturi
air-aspirator Spray pressure 40-100 PSI
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Droplet size

• Droplet category Symbol VMD (µm)
• Very fine VF lt 150
• Fine F 150-250
• Medium M 250-350
• Coarse C 350-450
• Very coarse VC 450-550
• Extremely coarse XC gt 550
• 220 µm VMD droplet size recommended for
  fungicides
• Droplets lt 200 µm are driftable

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Droplet size

• VMD volume mean diameter
• half of spray volume is in droplets larger
  than this size and half is in droplets smaller

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XR TeeJet Flat Fan Nozzle
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Boom height

• Balance between canopy penetration and uniformity
• Lower boom height to
• reduce loss of fine droplets
• increase droplet penetration into canopy
• (wide angle nozzles (e.g. 110o) allow lower
  boom height)
• Need to maintain a minimum boom height for
  proper overlap between adjacent nozzles

20
50 overlap
10
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Fungicide Application Info

• Section 3 labels Spray volume (gpa)
• Bravo 20-150 (complete coverage)
• Echo 720 20-150 (complete coverage)
• Quadris sufficient volume for coverage
• Headline sufficient volume for coverage
• Section 18 labels
• Tilt 15 (35-40 psi at nozzles)
• PropiMax 15 (35-40 psi at nozzles)
• Bumper 15
• Folicur 10 (complete coverage)
• Laredo 15-20 recommended

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Section 18s

• Section 18 label must be in possession of the
  applicator during the application
• List of section 18 labels approved in Wisconsin
  http//www.datcp.state.wi.us/arm/agriculture/pest-
  fert/pesticides
• /special.html
• Site also contains some of the actual labels
• Some section 18 labels available at
• http//www.cdms.net/

13
Fungicide and herbicide tank mixtures

• Separate applications are generally best.
• Why?
• Timing
• Weeds V2-3 soybean stage
• Rust R1 stage stage?
• Drift
• Herbicides medium or coarse droplets
• Fungicides very fine or fine droplets
• Label recommendations for tank mixtures
• Not addressed on many labels (safest to avoid)
• or generic statements not recommending tank
  mixtures
• Few labels approve tank mixtures (e.g.
  Headline)

14
Drift

• Dont think drift doesnt matter with
  fungicides
• In Wisconsin, pesticide drift is
• readily visible or could or actually causes harm
  to persons, property or the environment
• (Quadris drift to apples is phytotoxic)
• Drift could
• cause illegal residues on adjacent crops
• reduce fungicide performance
• increase public concerns of pesticide
  applications

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Take Home Message

• Spray volumes that work with glyphosate in
  Roundup Ready soybeans (10-15 gpa) are too low
  for the best results for fungicides (15 gpa
  minimum 20 gpa better)