QUALITY ADJUVANTS by utw83BYT

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									QUALITY ADJUVANTS

Importance & Economics
     Barriers of Entry
     Mode of Action
          Quality
    Importance & Economics
   What value does the adjuvant bring?




      Without adjuvants many herbicides would not perform!
    Importance & Economics
Dr. Jerry Green - DuPont - Program Leader for Adjuvants
   “Adjuvants are helping shift the herbicide market from
   preventive soil applications at high rates to curative
   applications applied directly to the weeds at low rates.”



    – post applied treatments are increasing
    – about 54% of corn, 79% of soybeans and
      90% of wheat receive a post herbicide
      application
Importance & Economics
Importance & Economics
    QUALITY ADJUVANTS
An adjuvant is…or could be...
  surfactant crop oil methylated seed oil fertilizer
      antifoamer defoamer     compatibility agent
Adjuvant - a material added to a tank mix to aid or
modify the action of an agrichemical, or the physical
characteristics of the mixture.

  “All surfactants are adjuvants, but not all
         adjuvants are surfactants…”
QUALITY ADJUVANTS

 Importance & Economics
  Barriers of Entry
     Mode of Action
        Quality
            Barriers of Entry

   Multiple Barriers of Entry
    – Leaf angle
    – Leaf hairs or pubescence
    – Leaf surface or cuticle
    – Cell wall or membrane


    The herbicide must pass through these
    barriers and translocate to be effective.
               Barriers of Entry
Leaf angle




Common sense, but often overlooked.
Grasses are smaller target versus broadleaves.
               Barriers of Entry
   Leaf hairs (pubescence)




Absorption dependent on good leaf-to-spray contact.
Some weeds are very hairy...microscopically.
                Barriers of Entry
   Leaf surface or cuticle




Made up of many parts; waxes - oil soluble or lipophilic,
cutin - water soluble or hydophilic, pectin - water soluble
pathways for entry.
              Barriers of Entry
   Cell Wall or membrane




Ammonium ions drive ion trapping.
              Barriers of Entry
   Translocation




Different herbicides
translocate differently.
QUALITY ADJUVANTS

 Importance & Economics
    Barriers of Entry
   Mode of Action
        Quality
               Mode of Action
   How does the adjuvant help penetrate
    these barriers?
    It depends on the adjuvant used...
    – Activator Adjuvants
       •   Nonionics surfactants
       •   Crop oil concentrates
       •   Methylated seed oils
       •   Nitrogen fertilizers
             Mode of Action
   Nonionic surfactants affect
    – spray solution
    – the surface of plant tissue
    – the cuticle surface
    – the cuticle layers
Facilitates wetting, more uniform spreading,
dispersing,solubilizing, and emulsifying for enhanced
herbicide uptake.
Decreases surface tension, slows drying time,
increases penetration.
            Mode of Action
   Nonionic surfactants
    – Combined water-loving and oil-loving
      properties...referred to as HLB Value
      • Hydrophilic-lipophilic balance
    – HLB Value is very important
      • 1 = oil loving...20 = water loving
    – The higher the HLB Value, the better the
      effectiveness with most water soluble
      herbicides.
               Mode of Action
   Crop oil concentrates
     – petroleum based with surfactants/emulsifiers
     – 80/20 or 83/17 (COC + surfactants/emulsifiers)

    Both the oil and type of surfactants enhance activity.

     – oil facilitates the penetration of the cuticle
     – emulsifier/surfactant allows oil to mix with water &
       assist in uptake of herbicide
     – commonly used when stress conditions exist
              Mode of Action
   Methylated Seed Oils
    – free fatty acids derived from soybean, corn,
      sunflower oils then reacted with methanol yielding
      methyl esters
         The most active activator adjuvants.




       performs very well on large or drought stressed weeds
            Mode of Action
   Methylated Seed Oils
    – MSOs are better spreaders versus COCs
    – high boiling point allows less evaporation -
      increasing the absorption
    – remains an oily liquid on the leaf - doesn’t
      dry to a salt crystal
    – similar in structure to cuticular waxes -
      causing “swelling” of waxes - increasing
      penetration
Mode of Action
               Mode of Action
   Nitrogen fertilizers
    Namely AMS or UAN
    – recently of greater interest
    – used alone or often with other adjuvants
    – ammonium and sulfate ions are key
Often specific with weed/herbicide or environmental conditions.
Relative analysis: Ammonium Nitrate                  Urea    Sulfate
        AMS =          21                  0          0        24
        UAN =           7                  7          14        0
         Rule of thumb…1 # of AMS ~1 qt of UAN for NH4
                   Little if any sulfate benefits with UAN
             Mode of Action
   Fertilizers
    – AMS
       • solves hard water antagonism
           – Ca, Mg, Zn, Na, Al or Fe
       • assists in uptake via “ion trapping”
QUALITY ADJUVANTS

 Importance & Economics
    Barriers of Entry
     Mode of Action
        Quality
                      Quality
   Quality Rating System
Developed to overcome confusion and communicate the
  important criteria of a high quality adjuvant.


Quality Rating System was developed in consultation
with manufacturers of pesticides and adjuvant suppliers.

Dr. Richard K. Zollinger-NDSU-Ext. Weed Control
“Yes, there is a difference among adjuvants - All
adjuvants are NOT created equal.”
                           Quality
   Nonionic Terms
    important criteria for selecting a high quality surfactant
    virgin ingredients             active ingredients
         HLB Value                 surfactant load
    antifoam index



          Should be stated on the label !
               Puts more validity into the marketplace.
                        Educates the buyer.
                            Quality
   COC/MSO Terms
    (important criteria for selecting a high quality surfactant - in
    addition to the nonionic terms)


                 oil load       oil type            viscosity
              paraffinic hydrocarbon              unsulphonated
                              residue


          Should be stated on the label !
                Puts more validity into the marketplace.
                         Educates the buyer.
   Chemical Producers & Distributors Association
• Labeling and Performance Standards for Spray Adjuvants
• Look for some changes in 2001.
• Adopted July 16, 2000.
• Voluntary


  Functionality claims ASTM Standards
  CFR 40, 180.1001       DOT Packaging
  Signal Words           Acute toxicity
           % Surfactant Load
            Oil Type Description
         Unsulphonated Oil Residue
    Good Manufacturing and Stewardship
                Practices
                 Costs to Certify
QUALITY ADJUVANTS

Importance & Economics
   Barriers of Entry
    Mode of Action
        Quality
QUESTIONS AND ANSWERS

								
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