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Application Techniques

Application Techniques. Chris Boerboom Extension Weed Scientist University of Wisconsin. 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 -

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Application Techniques

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  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 • PressureRating • XR TeeJet (flat fan) > 30 psi Excellent • XR TeeJet (flat fan) < 30 psi Good • TwinJet Excellent • Turbo TeeJet > 30 psi Very good • Turbo TeeJet < 30 psi Good • Standard flat fan Good • Air induction Good • Hollow disc-cone (banding nozzle) Good

  5. Nozzle types Excellent spray distribution over a wide range of pressures: 15-60 PSI Reduces drift at lower pressures, better coverage at higher pressures • XR TeeJet flat fan TwinJet • Turbo TeeJet 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

  6. 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

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

  8. 200 µm 400 µm = Droplet size • VMD = volume mean diameter • = half of spray volume is in droplets larger than this size and half is in droplets smaller

  9. XR TeeJet Flat Fan Nozzle

  10. 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”

  11. 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

  12. 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 • Don’t think “drift doesn’t 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

  15. 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)

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