The Role of Adjuvants in the DRT Program:
Perspectives of an Adjuvant Manufacturer
Johnnie R. Roberts
Director of Formulation Development & Technical Support
HELENA CHEMICAL COMPANY
The Role of Adjuvants in the
DRT Program
• Direct use as a DRT
• Enhancement of Pesticide formulation DRT
• Enhancement of Equipment DRT (nozzles)
• Prevention of application and efficacy problems
caused by DRT
The Role of Adjuvants: Direct
Use as a DRT
• Fifty+ years of commercial history (Poly acrylamide
patent filing – 1964!)*
• Proven ‘stand‐alone” capabilities for minimizing driftable fine formation
• Continual technology refinement & confirmation of effectiveness
*US Patent# 3,360,356 Filed 05/27/1964
The Role of Adjuvants: Enhancement of Pesticide Formulation DRT
• Long established use as “compliments” to the deposition performance of pesticide formulations
• Used to off‐set the driftable fine formation of low spray volume applications
The Role of Adjuvants: Enhancement of Spray Application Equipment DRT
• Demonstrated ability to increase the performance of DRT equipment (e.g Air induction nozzles)
• Spray mix modifications with specialized adjuvants that work in conjunction with equipment (THIN‐VERT®)
The Role of Adjuvants: Prevention
of application and efficacy problems
caused by DRT
The introduction of
new technologies
Often create new
and unexpected
“opportunities”
Examples of Application and Efficacy Problems that can be caused by DRT
• Loss of efficacy due to coarse droplet formation
• Spray mix compatibility
• Foam generation
• Antagonisms
13.36 GPA
9.09 GPA
4.81GPA
28 days after application of 2,4‐D ester phenoxy herbicide
Very coarse vs. Fine
Picture Courtesy of Dr. Richard
Zollinger ‐ NDSU
Adjuvants may off‐set Efficacy
loss caused by: • Enhancing the degree and rate of a.i. absorption
• Reducing droplet bounce
• Off‐setting water quality problems / antagonisms
• Increasing coverage of the spray deposit • Reducing spray deposit evaporation
Examples of Potential Spray Mix Incompatibilites
High viscosity
Emulsion break‐down
Sediment formation
Hard‐packing of sediment (poor re‐dispersion)
• Screen‐blockage
•
•
•
•
Adjuvants may prevent Compatibility Problems by:
• Reducing spray viscosity
• Improving spray mix uniformity
• Dispersing agglomerates
• Increasing spray mix sediment re‐dispersibility
With Spray
Adjuvant
W/O Adjuvant
Sediment
fixed to the bottom
Sediment flows
across the bottom
Alone
With Spray Compatibility Adjuvant
Examples of Potential Spray Application problems caused by Foam
• Increased formation of driftable fines
• Difficulty in maintaining spray calibration
• > Spray mix preparation problems • > Worker exposure
Spray adjuvants may reduce foam generation in DRT applications by:
• Minimizing foam formation (e.g. oils)
• Preventing foam generation (e.g. anti‐
foam agents)
• Correcting foam generation (e.g. de‐
foamers)
The Role of Adjuvants in the
DRT Program: Limitations
• Adjuvant inclusion must not interfere with formulation and equipment DRT
• Methods / protocols for measuring impact of adjuvants on DRT are variable and/or not fully established
The Role of Adjuvants in the
DRT Program: Limitations (II)
• Components used in the manufacture of adjuvants must be cleared for use as pesticide ingredients. High cost for securing clearance limits new technology • Perception is reality
DRT: Perception is Reality for both growers and the Public • Visual spray droplets = Perception of “drift”
• Odor = Perception of spray droplet drift
• Perception that volatility and spray droplet drift are the same
The Role of Adjuvants in the
DRT Program: NEEDS
• Well defined / consistent testing protocols for measuring the impact of adjuvants on DRT
• > Number of pesticide cleared formulation components
• Clear pesticide label language for adj. recommendations • > Grower / applicator training on the role of adjuvants in DRT
Thank You!