QUALITY ADJUVANTS

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QUALITY ADJUVANTS

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

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Importance Economics

• What value does the adjuvant bring?
• Without adjuvants many herbicides would not
  perform!

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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

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Importance Economics
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Importance Economics
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QUALITY ADJUVANTS
An adjuvant isor could be... surfactant crop
oil methylated seed oil fertilizer antifoame
r 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
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QUALITY ADJUVANTS

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

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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.

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Barriers of Entry

• Leaf angle
• Common sense, but often overlooked.
• Grasses are smaller target versus broadleaves.

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Barriers of Entry

• Leaf hairs (pubescence)
• Absorption dependent on good leaf-to-spray
  contact.
• Some weeds are very hairy...microscopically.

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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.

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Barriers of Entry

• Cell Wall or membrane
• Ammonium ions drive ion trapping.

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Barriers of Entry

• Translocation
• Different herbicides
• translocate differently.

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QUALITY ADJUVANTS

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

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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

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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.

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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.

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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

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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
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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 - doesnt dry
  to a salt crystal
• similar in structure to cuticular waxes - causing
  swelling of waxes - increasing penetration

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Mode of Action
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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 thumb1 of AMS 1 qt of UAN for NH4
• Little if any sulfate benefits with UAN

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Mode of Action

• Fertilizers
• AMS
• solves hard water antagonism
• Ca, Mg, Zn, Na, Al or Fe
• assists in uptake via ion trapping

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QUALITY ADJUVANTS

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

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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.

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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.

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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.

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• 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
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QUALITY ADJUVANTS

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