PESTICIDES AND PROTECTING
YOUR ENVIROMENT
When using pesticides, what are the….
Non- target species Pest susceptibility
Effects on and in the immediate
environment?
Soil type Weather
SENSITIVE AREAS
Pesticide Movement
ON OR IN SOIL,
PLANTS, CLOTHING,
ANIMALS
AIR - DROPLETS WATER
• Droplets
• Vapor
• Pesticide bound to dust or soil
Physical Drift Vapor or
Chemical Drift
Physical Drift
& Droplet Size Smaller
Larger
Comparison of Micron Sizes
(approximate)
• 2000 m #2 Pencil lead
• 850 m paper clip
• 420 m staple
• 300 m toothbrush bristle
• 150 m sewing thread
• 100 m human hair
Nozzle Drop Size Classes
Very Fine to Fine 450 um
Tip Spray Selection by Drop Size
Turbo TeeJet Flat-fan
Sources of Spray Mist or Fines
Aerodynamic Effects
Air friction due to speed of the application
vehicle causes additional production of
small droplets
Sources of Spray Mist or Fines
Secondary Break-Up
Droplet elongation and fracture
produces small droplets
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Sources of Spray Mist or Fines
Aerodynamic Effects
Movement
Air friction due to speed of the application
vehicle is dependent upon the nozzle
orientation angle. 90o produces the greatest
number of small droplets
Spray Tip Height
Moves the droplets!
Driftability of Spray
Droplets of Varying Sizes
Crosswind @ 3 mph
20
50
10 feet
100
150
400
8 ft 22 ft. 48 ft. 178 ft. 1065 ft.
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Air Temperature & Evaporation
77oF
2nd Type of Drift
Vapor Drift
Pesticide Volatility
Vapor
Drift
• Pesticide changes into a gas
-- the pesticide evaporates!!
• Moves from the target area
Vapor Pressure
• Vapor pressures vary widely among
pesticides.
• The least volatile pesticides:
– salts and acids
• Pesticide more prone to volatize:
– phenols and esters
Volatility
• Conversion of a liquid or solid to a gas
• Lower vapor pressure = lower volatility
• EPTC – 3.4 x 10-2 mm Hg
• Fargo – 1.1 x 10-4 mm Hg
• 2,4-D ester = 13 mPa
• Banvel = 4.5 mPa (9x10-6 mm Hg)
• Banvel SGF = 1.6 mPa
• Tordon = 0.082 mPa (6x10-7 mm Hg)
• Roundup = 0.010 mPa (2x10-7 mm Hg
Volatility is also affected by:
• Weather
– High temperatures
• 2x more 2,4-D
ester volatilizes at
80o than 70o
– Low humidity = more
volatilization
– Air Inversions
• Droplet Size
• Wind -- 85 F
• Know your surroundings
• Calibrate equipment
• Mix properly
• Read and heed all labels.
Pesticide Losses at Application
Pesticide Losses In Water
• Leaching
• Run off
• Spills and backsiphoning
• Improper disposal
Solubility
• Amount of chemical • Tordon = 400- 430
that can be dissolved • 2,4-D = 890
into a solution • Assert = 1370
• Ally/Escort
• Expressed as parts – 1750 (pH 5)
per million. – 2790 (pH 7)
– 213,000 (pH 9)
• > 30 ppm means high
• Paraquat = 7000
solubility = high
• Roundup = 15,700
tendency to leach or
– 900,000
runoff.
Runoff vs.
Leaching
Adsorption
• The binding of a
pesticide molecule to
a soil particle
• Mostly due to
organic matter that
coats the soil particle
• More organic matter
= more binding by
less-soluble pesticides
Koc of Common Pesticides
• Banvel – 2 • Methyl Parathion – 5100
• Stinger – 6 • Lorsban - 6070
• Pursuit – 10 • Treflan – 7000
• Tordon – 16 • Roundup – 24,000 *
• Buctril – 10,000
• 2,4-D – 20
• Capture – 216,500
• Assert – 35 to 66
• Paraquat – 1,000,000
• 2,4-D Ester – 100
• MCPA – 110 * binds tight but also highly
• Broadstrike - 700 water soluble
Some things to ponder
• Read the label!
– Look for restrictions based on soil type.
Example – restrictions on loamy sand to
sandy soils.
• Calibrate! Calibrate! Calibrate!
• Do not over apply
• Know the soil type in the area you are
spraying. Conduct a soil test….
Texturing your soils
Even a jar test will give you an
idea!
Persistence
(Residual)
• Degradation
– Microbes (#1)
– pH (#2)
– Sunlight
– Rate applied
• Degraded over time to produce CO2, H2O, N, P, Su,
• Expressed as “half-life.”
• Time required for that substance to degrade to one-half
its previous concentration.
Degradation values of some common
pesticides (1/2 life in days)
• Malathion - 1
• 2,4-D - 10
• Banvel – 14
• Ally, Amber – 30
• Stinger - 40
• Assert – 45
• Roundup - 47
• Tordon – 90 to 180
• Spike - 360
• Paraquat – 1000
Protecting Water Resources
Protect your wells!
Protecting Water Resources
• Practice IPM
• Environmental considerations
• Well Locations?
• Calibrate and use only what is needed
• Mix and load carefully
• Prevent back-siphoning
• Consider the weather
• Select, store and dispose of pesticides carefully
Disposal of Pesticides &
Containers
• Know the size of the area you want to
spray.
• Know how to calibrate a sprayer.
• Know how to mix pesticides
• Buy mix, apply and store only what you
need!!
Triple Rinsing
Containers
Triple Rinsing
Containers
• Triple rinsed within 48
hours of being emptied
• Must be triple rinsed for
landfill disposal
• Never use pesticide containers for other purposes
• Burning of pesticide containers is not allowed
Montana Department of Agriculture
Waste Pesticide Program
http://mtpesticides.org