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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.