1. Herbicide Formulations
Plant Science 280
Mr. Gomes

2. Formulation All herbicides are formulated
Liquid
Solid
Formulations vary for different methods of applications
Selectivity
To facilitate use
Increase effectiveness
It is a physical, not chemical mixture

3. Formulation Basics Chemists have two primary goals;
Improve biological effectiveness
Place a herbicide in a physical form that is convenient for users
The chemical industry is dominated by
Arysta, BASF, Bayer, Isagro, Chemtura, Dow, DuPont, FMC, NuFarm, Monsanto, Syngenta, Valent
What does the global impact of merging lately mean?

4. Types of Formulations - Liquid
Solution Concentrate
Usually require little formulation and have high concentrations: Acidic Salts
Emulsified Concentrate
Herbicide dissolved in an organic solvent. Acts like oil and water when formulated
Invert Emulsions
More viscous and produce larger droplets
Flowable Concentrate
No organic solvent, and are insoluble in water.
Encapsulated
Encapsulated dry or liquid herbicide in microscopic polymer

5. Types of Formulations - Dry
Dusts and Dry Powders
Fine powder, insecticides
Wettable Powders
Dust like solids that easily suspended in water. Plug
Granules
Used as soil applied
Dry Flowable and Water-Dispersible Granules
Water-Soluble Packets and Effervescent Tablets
Other

6. Surfactants and Adjuvants
Surface active agent
Increase wettability and spread ability
Enhance Phytotoxicity and Penetration
Adjuvants
Promote foliar activity and absorption
Safeners or protectants
Buffering Agents, antifoam, drift control

7. Factors Affecting Herbicide Performance
Sprayer Calibration
Droplet size and rate
Drift
Windspeed and height above the ground - liquid
5 mph industry standard
Can move anywhere from 5 feet to 3 miles
Volatility
Tendency of a chemical to vaporize
Liquid to gas

8. Foliar Active Herbicides: Factors
Spray Retention: Staying on the leaf
Leaf Properties: broadleaves, grasses, etc
Spray Solution: High surface tension and drop size
Others: Growth stages, nodes, meristemic areas
Environmental Factors
Moisture: weather (rain, dry, wet, hot, cold)
Temperature: hot versus cold
Light: open stomate and photosynthetic rate

9. How Herbicides Work in Plants
Foliar Absorption
Absorption from Soil
Translocation
Metabolism

10. Foliar
The application of a herbicide directly on the plant tissue itself
Once on the leaf, most occur through Cuticular penetration
Generally a highly efficient method
Can be used to control specific, observable weed problems
Timing can be a detriment

11. Absorption from Soil Advantages Include; Disadvantages Include
Much more convenient
Not dependent on growth stage
Disadvantages Include
Dilution
Fixation by soil colloids
Residuals

12. Translocation The movement of herbicides inside the plant
Occurs through the Phloem and Xylem
Phloem occurs source to sink
Maturity of the plant determines where translocation occurs