pesticide drift management dr. eric p. prostko extension weed specialist university of georgia

Pesticide Pesticide DriftDrift

ManagemeManageme

ntntDr. Eric P. Prostko

Extension Weed SpecialistUniversity of Georgia

Pesticide Drift ManagementPesticide Drift ManagementTopics For DiscussionTopics For Discussion

definitiondefinition types of drifttypes of drift factors affecting factors affecting

driftdrift equipmentequipment managementmanagement

What is pesticide drift??What is pesticide drift??

the movement the movement of the pesticide of the pesticide away from the away from the target area.target area.

physical driftphysical drift vapor driftvapor drift

Spray drift is undesirable!!Spray drift is undesirable!!

inefficient use of equipment and timeinefficient use of equipment and time under-application/ineffective controlunder-application/ineffective control litigation concernslitigation concerns unintentional contamination of unintentional contamination of

foodstuffsfoodstuffs air/water pollutionair/water pollution livestock and human health/safetylivestock and human health/safety

Corn and Grain Sorghum Yield Loss From Corn and Grain Sorghum Yield Loss From Simulated Staple Drift, College Station, Simulated Staple Drift, College Station,

1994.1994.

27

7

40

20

61

33

84

54

020406080

100

Corn Sorghum

Crop

Yiel

d Lo

ss (%

)

1.50% 3.00% 6.00% 12.00%

Applied 30 DAPApplied 30 DAP

Physical DriftPhysical Drift

movement of movement of pesticide away pesticide away from target during from target during applicationapplication

droplet sizedroplet size boom heightboom height weatherweather

Studies have shown that Studies have shown that equipment and its operation equipment and its operation are responsible for 68-90% are responsible for 68-90% of the physical drift problems of the physical drift problems while weather accounts for while weather accounts for 10-32%.10-32%.

D. B. Smith et al., 1982

Physical DriftPhysical DriftDroplet SizeDroplet Size

measured in micronsmeasured in microns hair - 50 micronshair - 50 microns 20-370 micron range20-370 micron range 200 micron average200 micron average smaller drops increase smaller drops increase

drift potential (< 100)drift potential (< 100)

Fall Rate of Various Size Fall Rate of Various Size DropletsDroplets

Droplet Diameter(microns) Time to Fall 10’

20 4 mins.

100 11 secs.

240 5 secs.

400 2 secs.

Relationship of Particle Size to Relationship of Particle Size to DriftDrift

DropDiameter(microns)

Particle Type

Drift Distance

400 Course 8.5

150 Medium 22.0

100 Fine 48.0

Based upon 10’ fall in 3 MPH windsBased upon 10’ fall in 3 MPH winds

Physical DriftPhysical DriftDroplet SizeDroplet Size

nozzle selectionnozzle selection Drift Guard NozzlesDrift Guard Nozzles

* * reduces volume of reduces volume of

droplets below 200droplets below 200

microns up to 65%microns up to 65% Raindrop NozzlesRaindrop Nozzles

* 0.7% - 200 microns* 0.7% - 200 microns

or lessor less

Physical DriftPhysical DriftSpray Boom HeightSpray Boom Height

SprayAngle 20” 30”

65 22-24 33-35

80 17-19 24-26

110 15-18 20-22

Spacing

** Wide-angle nozzles Wide-angle nozzles can be placed lower can be placed lower to the ground but also to the ground but also produce smaller produce smaller droplets.droplets.

** Easy and inexpensive Easy and inexpensive

Physical DriftPhysical DriftWeatherWeather

wind wind speed/directionspeed/direction

* * most importantmost important temperaturetemperature humidityhumidity inversionsinversions

Physical DriftPhysical DriftTemperature InversionsTemperature Inversions

NormalNormal InversionInversion

Physical DriftPhysical DriftOther Factors to ConsiderOther Factors to Consider

nozzle nozzle orientationorientation

spray pressurespray pressure spray volumespray volume

Physical DriftPhysical DriftNozzle OrientationNozzle Orientation

ground speeds ground speeds > 10 MPH> 10 MPH

454500 or more or more from from perpendicularperpendicular

30% < 100 microns30% < 100 microns 88% < 100 microns88% < 100 microns

Influence of Spray Pressure on Influence of Spray Pressure on Droplet SizeDroplet Size

Flat Fan Nozzle - 0.6 GPMFlat Fan Nozzle - 0.6 GPM

12

6

0

5

10

15

20 PSI 40 PSI

Pressure

% D

ropl

ets

100

mic

rons

or

less

Physical DriftPhysical DriftSpray VolumeSpray Volume

most effective means to increase most effective means to increase spray volume is to increase nozzle spray volume is to increase nozzle orifice sizeorifice size

i.e. 8002 vs. 8003 vs. 8004i.e. 8002 vs. 8003 vs. 8004

Vapor DriftVapor Drift

the volatilization or evaporation of a the volatilization or evaporation of a pesticide from the soil or crop surface pesticide from the soil or crop surface that occurs after application.that occurs after application.

Factors that influence vapor drift Factors that influence vapor drift include:include:

** vapor pressure/volatilityvapor pressure/volatility

* * temperaturetemperature

* * wind speedwind speed

Non-TargetSensitive Crop

Vapor drift can occur even days after the application

Wind

Drift

Vapor

Vapor Pressure Values of Various Vapor Pressure Values of Various ChemicalsChemicals

@ 77@ 7700FFChemical mm Hg X 0.000001Atrazine 1Banvel 342,4-D (LVE)2,4-D (HVE)

2001400

Sutan 13,000Water 24,6000,000

Note: The higher the number the more volatile the chemical.Note: The higher the number the more volatile the chemical.

Pesticide Drift ManagementPesticide Drift ManagementEquipment ModificationsEquipment Modifications

shielded spray shielded spray boomboom

covered boomcovered boom hooded-sprayershooded-sprayers air-assist systemsair-assist systems electrostatic electrostatic

sprayingspraying

Pesticide Drift ManagementPesticide Drift ManagementDrift Control AgentsDrift Control Agents

“ “thickeners”thickeners” increase droplet size of pesticide/water increase droplet size of pesticide/water

mixesmixes $0.10-$1.00/A$0.10-$1.00/A 38F, Anchor, Array, Border, Chem-Trol, 38F, Anchor, Array, Border, Chem-Trol,

Corsair, Direct, Drifgon, Driftgard, Drop Corsair, Direct, Drifgon, Driftgard, Drop Zone, Get Down, Lo-Drift, More, Nalcotrol, Zone, Get Down, Lo-Drift, More, Nalcotrol, Submerge, Sta-Put, WindfallSubmerge, Sta-Put, Windfall

Drift Fallout As Influenced By Drift Fallout As Influenced By Pressure and NalcotrolPressure and Nalcotrol

2.8

3.9

11.5

0

1

2

3

4

5

30 40

PSI

Dri

ft Fa

llout

(%

)

- Nalcotrol+Nalcotrol

Source: W. Bowers. 1975. Ohio State Univ. Extension, Facts #1203.Source: W. Bowers. 1975. Ohio State Univ. Extension, Facts #1203.

Top 10 Tips For Reducing Top 10 Tips For Reducing Pesticide DriftPesticide Drift

nozzle selectionnozzle selection reduce pressurereduce pressure lower boom heightlower boom height increase nozzle increase nozzle

sizesize avoid spraying avoid spraying

when winds exceed when winds exceed 10 MPH10 MPH

lookout for lookout for inversionsinversions

use additivesuse additives calibrate sprayercalibrate sprayer keep recordskeep records use common use common

sensesense

References used in the References used in the development of this slide set development of this slide set

include the following:include the following: Reducing Spray Drift. Ohio State Reducing Spray Drift. Ohio State

Univ. Extension Bulletin 816, H. Univ. Extension Bulletin 816, H. Erdal Ozkan.Erdal Ozkan.

Herbicide Application Herbicide Application Management. Sandoz Crop Management. Sandoz Crop Protection, 1993.Protection, 1993.