PESTICIDES AND PROTECTING YOUR ENVIROMENT

Effects on and in the immediate environment? When using pesticides, what are the…. Non- target species Pest susceptibility Effects on and in the immediate environment? Weather Soil type SENSITIVE AREAS

ON OR IN SOIL, PLANTS, CLOTHING, ANIMALS Pesticide Movement ON OR IN SOIL, PLANTS, CLOTHING, ANIMALS AIR - DROPLETS WATER

Vapor or Chemical Drift 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) #2 Pencil lead paper clip staple toothbrush bristle sewing thread human hair

Nozzle Drop Size Classes Very Fine to Fine < 200 um Medium to Coarse – 200 to 450 um Very Coarse > 450 um

Tip Spray Selection by Drop Size Turbo TeeJet Flat-fan This slide represents an example of the choices an applicator would have within a single nozzle type. If the label suggested a medium sized spray droplet and the applicator wanted to use the specific nozzle type shown, then all the light blue areas in this particular chart would represent a proper selection. This would allow for maximum flexibility as application conditions changed form day to day and even during the day. As an example, as wind speed increased, or the temperature increased and humidity dropped, choosing to operate at a lower pressure making bigger drops should minimize the drift potential.

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 \

Sources of Spray Mist or Fines Aerodynamic Effects Air friction due to speed of the application vehicle is dependent upon the nozzle orientation angle. 90o produces the greatest number of small droplets Movement

Spray Tip Height

WIND Moves the droplets!

Driftability of Spray Droplets of Varying Sizes Crosswind @ 3 mph 20 m 50 m 100 m 150 m m 8 ft 22 ft. 48 ft. 178 ft. 1065 ft. 10 feet \

Air Temperature & Evaporation 77oF

2nd Type of Drift Chemical Drift Vapor Drift Pesticide Volatility

Vapor Drift Pesticide changes into a gas -- the pesticide evaporates!! Moves from the target area Vapor drift, also known as chemical drift and occurs when a pesticide changes from its liquid or solid state in to a gas. Once the pesticide evaporates, or volatizes, it can move from the target area. All pesticides are prone to physical drift as spray droplets, but some pesticides like the herbicides 2,4-D ester and MCPA ester can produce damaging vapors due to their ability to convert readily to a gas at a given temperature. Up to 30% of a volatile pesticide can drift as vapor in the first 30 minutes after application.   Vapor pressure is just one chemical property of a pesticide that affects vapor drift. Vapor pressure is a measure of a pesticides tendency to evaporate.Vapor pressures vary widely among pesticides. The least volatile pesticides are salts and acids while phenols and esters are more prone to vapor drift. The higher the vapor pressure, the more likely a pesticide will volatize.

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 -- < 10 MPH & away from sensitive areas Choose formulation wisely Drift control additives Apply early morning or late evening. Higher humidity. Air Inversions! Avoid high temps > 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 that can be dissolved into a solution Expressed as parts per million. > 30 ppm means high solubility = high tendency to leach or runoff. Tordon = 400- 430 2,4-D = 890 Assert = 1370 Ally/Escort 1750 (pH 5) 2790 (pH 7) 213,000 (pH 9)  Paraquat = 7000 Roundup = 15,700 900,000

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 Stinger – 6 Pursuit – 10 Tordon – 16 2,4-D – 20 Assert – 35 to 66 2,4-D Ester – 100 MCPA – 110 Broadstrike - 700 Methyl Parathion – 5100 Lorsban - 6070 Treflan – 7000 Roundup – 24,000 * Buctril – 10,000 Capture – 216,500 Paraquat – 1,000,000 * binds tight but also highly water soluble

Some things to ponder Read the label! Calibrate! Calibrate! Calibrate! 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