Managing Pesticide Drift Mary Beth Henry Aquatic Weed ... · Managing Pesticide Drift Mary Beth...

Managing Pesticide DriftMary Beth Henry

Aquatic Weed Short CourseMay 5, 2010, Coral Springs Marriott

Learning Objectives

• What spray drift is

• How environmental factors affect drift

• The effects of droplet size

• How your decisions can affect spray drift

UF/IFAS PIO

What is Drift?

Unknown Photo Source

The physical movement of pesticide through the air at the time of pesticide application or soon thereafter from the target site to any non- or off-target site.

What isn’t Drift?

• Pesticides moved by:

– Erosion

– Migration

– Volatility

– Windblown soil particles


Types of Drift

• Vapor Drift - associated with volatilization, gases, fumes

• Particle Drift - movement of spray particles


Why All the Interest in Drift?

• Spotty pest control

• Wasted chemicals

• Off-target damage

• Environmental impact

– Water and Air Quality

• Public more aware of pesticide concerns

• Spraying in more populated areas



• Because drift can cause injury to:– Adjoining crops– Livestock– Wildlife– Humans

• Because drift costs money:– Restitution for damaged crops– Reduced control of intended target pest(s)– Increased regulations because of drift problems

Detrimental effects of driftReduced application rate on target pestApplying pesticides in a manner that allows drift to occur is a label violation

Recent EPA Activity

a. Draft label changes regarding drift

b. Comment period closed 3/5/10

c. 935 submissions

9

What are the major factors in managing drift?

a. Droplet size

b. Wind speed and direction

c. Chemical and formulation

d. All of the above

10

What are the major factors in managing drift?

a. Droplet size

b. Wind speed and direction

c. Chemical and formulation

d. All of the above

11

Factors Affecting Drift

• Chemical

• Formulation

• Additives

• Drop size

• Evaporation



• Environmental Factors– Wind speed and direction

– Temperature and humidity

– Air stability/inversions

– Topography



• Equipment & Application

–Nozzle type

–Nozzle size

–Nozzle orientation

–Nozzle pressure

–Height of release

–Technology

UF/IFAS PIO

What is the target minimum droplet size to reduce drift:

a. 50 μm

b. 100 μm

c. 200 μm

d. 350 μm

15

What is the target minimum droplet size to reduce drift:

a. 50 μm

b. 100 μm

c. 200 μm

d. 350 μm

16

Droplet Size• Large droplets have less potential to drift because

they:– Fall more quickly– Evaporate more slowly– Are less affected by wind

• Small droplets often result from:– High spray pressure– Small nozzle tips– Wind shear across the nozzles

UF/IFAS PIO

Droplet sizeDroplet diameter is measured in microns (μm)

1 μm = 0.001 mm = 0.0001 cm

Type of droplet Diameter (μm)Smoke <1

Fog 15Mist 50

Grain of salt 100Rain 500

Comparison of Micron Sizes for Various Items (approximate)

• 2000 μm

• 850 μm

• 420 μm

• 300 μm

• 150 μm

• 100 μm

#2 Pencil lead

paper clip

staple

toothbrush bristle

sewing thread

human hair

150

One micron (μm) =1/25,000 inch

Relationship of Drift to Drop Size

Volume Median Diameter (VMD)

Spraying Systems Co.

3 mph windD

ropl

et re

leas

e: 3

ft. a

bove

gro

und

Small droplets

Large droplets

Droplet sizeDroplet size is influenced by nozzle orifice size and spray pressure

At a given pressure, droplet size decreases as nozzle orifice size decreasesAt a given nozzle orifice size, droplet size decreases as spray pressure increases

Labels and Droplet Size

CDMS

Droplet spectrum1

Contact insecticide & fungicide

Systemic insecticide & fungicide

Contact foliar herbicide

Systemic foliar herbicide

Soil-applied herbicide

Incorpor-ated soil-applied herbicide

Very fine (VF)

Fine (F) X

Medium (M)

X X X X

Coarse (C) X X X X

Very coarse (VC)

X X X

Extremely coarse (XC)

X

1Based on Volume Mean Diameter (VMD) designation.

Category (symbol) Color codeVery fine (VF) RedFine (F) OrangeMedium (M) YellowCoarse (C) BlueVery coarse (VC) GreenExtremely coarse (XC) White

ASABE Spray Quality Categories

Very fine

Fine Medium Coarse Very coarse

Extr.coarse

Increasing pressureIncreasing

orifice size

Droplet sizeUse nozzles with the largest orifice size that is appropriate for the applicationUse a spray pressure near the middle of the range for a given nozzle

Low Drift Nozzle Types

UF/IFAS PIO

Which Size is Best?

Western Crop Protection Association

Droplet sizeNozzle orifice size and spray pressure should maximize droplet size but still provide adequate coverageDroplets too big:Poor coverage

Good droplet size:Adequate coverage

Factors You Can’t Control• Weather

– Wind(speed & direction)

– Temperature

– Humidity

• Susceptible crops or other non-target areas of concern near your application site


Wind

UF/IFAS PIO

The range of wind speed to avoid drift is:

a. 0-3 mph

b. 2-5 mph

c. 3-10 mph

d. 6-12 mph

35

The range of wind speed to avoid drift is:

a. 0-3 mph

b. 2-5 mph

c. 3-10 mph

d. 6-12 mph

36

Wind

Kansas State University

Drift potential is lowest at wind speeds between 3 and 10 miles per hour

Wind


Temperature and Humidity

The faster they evaporate the more likely they are to reach a driftable size before reaching the target


Evaporation of DropletsHumidity effects on droplet size

70% RH 30% RH

Wind


• Temperature inversions


Radiant cooling of the ground

Drift Potential vs Inversions


Factors the Applicator can Control

• You can control…– The selection of the applicator/operator

– Equipment selection and setup

– Field conditions

– The choice of the product

UF/IFAS PIO

Equipment Selection and Setup

UF/IFAS PIO

Strategies to Reduce Drift: Equipment Setup

• Select nozzle to increase drop size• Increase flow rates - higher application volumes• Use lower pressures• Use lower spray (boom) heights• Drift reduction nozzles

UF/IFAS PIO


UF/IFAS PIO


Unshielded boom

Wil-Richshield

Wind Cones

AE shield

18’Vertical

2.47 1.51 1.43 1.51

100’Horizontal

4.19 1.57 1.93 1.56

TOTAL 6.66 3.08 3.36 3.07

Avg. wind speed

8.7 8.0 10.4 10.1


UF/IFAS PIO

Strategies to Reduce Drift: Electrostatic Sprayers


Strategies to Reduce Drift: Sensor-Controlled Sprayers

UF/IFAS Doc. HS-872

Strategies to Reduce Drift: Drift Reduction Additives

• Polyvinyl

• Polyacrylamide

• Linear alkyl epoxide

• Polymide copolymers

UF/IFAS PIO


Nozzle type Droplet size (micron)

Visible injury (meters)

Turbo TeeJet 250b 6.2a

Turbo FloodJet 261b 5.5a

Turbo Air Induction 284a 5.7a

XR Flat Fan (40 psi) 240c 8.1b

XR Flat Fan (20 psi) 222c 8.0b

University of Nebraska


University of Nebraska


UF/IFAS PIO

Strategies to Reduce Drift: Buffer Zones

CDMS

Product Selection

UF/IFAS PIO

Drift and the Law

Drift and the Law

• 2,4-D

• MCPA

• 2,4-DP

• MCPP

• MCPB

• Dicamba

• Triclopyr

UF/IFAS PIO

Drift and the Law

UF/IFAS Agronomy

Drift and the Law

UF/IFAS PIO

FDACS-13345

FDACS-13328

http://www.doacs.state.fl.us/onestop/forms/13328.pdf

A major ag insurance company categorized 1996 payouts due to misapplication. What percentage were due to drift?:

a. 33%

b. 48%

c. 17%

d. 68%

67

A major ag insurance company categorized 1996 payouts due to misapplication. What percentage were due to drift?:

a. 33%

b. 48%

c. 17%

d. 68%

68

Why All the Interest?

33%

33%

24%

8% 2%

Drift

Improper tank mix

Application Equipment

Off label application

Whoops

wrong field!

70

What percentage of drift incidences may be attributed to applicator judgment?:

a. 16%

b. 38%

c. 50%

d. 78%

71

What percentage of drift incidences may be attributed to applicator judgment?:

a. 16%

b. 38%

c. 50%

d. 78%


13%

26%

38%

23%

NozzleApplicatorPhysicalOther

Photo/Diagram Credits• Many slides from Fred Fishel “Pesticide Drift-Keeping it on Target “ (included slides from)• University of Florida/IFAS• Florida Depart. of Agriculture and Consumer Services• Kansas State University• University of Nebraska• US EPA• CDMS• National Coalition on Drift Minimization• Spraying Systems Co.• Western Crop Protection Association

• Additional Slides from Brandon Fast “Pesticide Drift "University of Florida,

Fred Fishel, Ph.D.Department of AgronomyUniversity of Florida/IFASCopyright 2009 University of Florida

Mention of trade names in this presentation is solely for providing specific information. It is not a guarantee or warranty of the products named, and does not signify that they are approved to the exclusion of others of suitable composition. Use pesticides safely. Read and follow directions on the manufacturer’s label.

Thanks!Mary Beth Henry

[email protected]

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