INAG 106
Pesticide Use & Safety Course
Lecture 12: Pesticide Application & Calibration
David Myers
Extension Educator,
Agriculture
myersrd@umd.edu
PESTICIDE CALCULATIONS
Determine the amount of
product needed
Formulated Product vs
Active Ingredient
Formulations and Active
Ingredient
Dry formulations will report
their active ingredient as a
% by weight
For example the label for
Thalonil states that it is a
90 DF product
Therefore the active
ingredient is 90% by weight
of the container
If the container weighs 5
lbs then .9 x 5 = 4.5 lbs
of active ingredient
Formulations and Active
Ingredient
Liquid formulations will report
their active ingredient in lbs
active ingredient per gallon and
as % by weight
For example the label for
Illoxan states that it is a 3 EC
formulation
This means that there is 3 lbs
of active ingredient per gallon
If the container size is 5
gallons then one would have
5 x 3 = 15 lbs of active
ingredient
Formulations and Active Ingredient
For example Diuron 4L is a liquid formulation
Its % active ingredient is 40%. To get the
amount of active ingredient in a gallon one
would have to multiply .40 by the weight of 1
gallon of this material
Since weight may not be given refer to the
lbs A.I. / gallon statement
FORMULATED PRODUCT
The Label Contains Information On The Amount
of Product Needed Under the “Directions For
Use” Section
How much Aliette would you need to make up 450 gallons if
you plan to use the lowest possible rate?
ANSWER
Set up a proportion as follows and solve for x
2.5 lbs
100 gallons
=
x____
450 gallons
Label Rate
(100) x (X) = (2.5) x (450)
X = (2.5) x (450)
100
X = 1125
100
X = 11.3 lbs of Aliette
ACTIVE INGREDIENT
If you want to solve for the amount of active
ingredient (A.I.) or if you are given the application
rate in lbs A.I. then use one of the following
formulas.
DRY MATERIAL
(% A.I. As a Decimal) (Form. Product) = lbs
of A.I.
LIQUID MATERIAL
lbs A.I = lbs A.I. Needed
gallon
formulated prod.
PRACTICE PROBLEM
If a 7.5 G insecticide is recommended at a rate of 4.5 lbs A.I./A,
determine how much of the formulated product is needed to treat
4 acres?
Use this formula:
(% A.I.) x (lbs of Formulated Product) = lbs of A.I.
(.075) x (X) = 4.5 lbs A.I.
X=
4.5
% A.I. needs to be
.075
expressed as a decimal
X = 60 lbs of product per acre
Remember you have to treat 4 acres therefore multiply 60 x 4
to get 240 lbs of insecticide for the 4 acre area.
PRACTICE PROBLEM
A 13,300 sq. ft. area needs to be treated with Daconil 4F.
How much Daconil 4F will be needed if you want to apply
3.5 lbs A.I.per acre.
Use the following formula for a liquid formulation:
4 lbs A.I.
1 gallon
=
3.5 lbs A.I.
X
Solve for X :
(4) x (X) = (1) (3.5)
X = 3.5
4
X = .88 gallons of
Daconil 4F is needed per
acre
You need to treat
a 13,300 sq. ft. area
13,300
43,560
= .305 of
an acre
(.88 gallons) X (.305 acre) =
.27 gallons of Daconil 4F will
be needed.
ACTIVE INGREDIENT
If you want to make up a % spray solution then the following
formulas can be used. One is for a dry formulation and the other
is for a liquid formulation
PERCENT CALCULATIONS
DRY
(Gallons Spray) (% Spray) (8.3)
% A.I. of Pesticide
LIQUID
(Gallons Spray) (% Spray) (8.3)
(lbs A.I. /Gallon) (100)
8.3 is a
constant and
represents the
weight of 1
gallon of
water
PRACTICE PROBLEM
You want to make up a 1.7% spray of Roundup 4 L. You have
a 250 gallon sprayer which you plan to fill. How much Roundup
will be needed? How much water will be needed?
Use this formula to solve the problem :
( % Spray ) ( Spray Volume) ( 8.3)
( lbs A.I./gallon) ( 100 )
( 1.7 ) ( 250 ) ( 8.3)
( 4 ) ( 100 )
3527.5
400
=
Amount of water needed =
=
[250 - 8.82] = 241.18 gallons
of water and 8.82 gallons of
Roundup will be added
to give 250 gallons of spray
8.82 gallons of Roundup 4 L will be needed
PRACTICE PROBLEM
You want to make up a .75% spray solution of Dursban 50 WP.
How much Dursban will be needed if you want to make up a 30
gallons?
Use This Formula :
( % Spray) ( Gallons of Spray ) ( 8.3 )
(% A.I.)
= (.75 ) ( 30 ) ( 8.3 )
50
=
186.75
50
=
3.7 lbs of Dursban 50 WP
Note: When using the
percent mix formulas
the % spray and % A.I.
Values are not entered
as decimals
PRACTICE PROBLEMS
1. If a 2.5G insecticide is applied at the rate of 3 lbs. A.I./A,
how much of the formulated product is needed to treat
5 acres?
Answer: 120 lbs/A and 600 lbs for 5 acres.
2. A 26,500 sq. ft area needs to be treated. The recommended
application much of the formulated rate is 1.8 lbs A.I./A.
The pesticide is formulated as a 2 EC. How much of the
formulated material will be needed to treat this site?
Answer: .55 gallon or 70 oz
PRACTICE PROBLEMS
3. A 1.7% spray of Weedbgone 4L is required for excellent
weed control. How much Weedbgone will be needed to treat
a 2 acre field? Assume that you want to mix the product in
water and apply the mixture at 1 gallon per 1,000 sq. ft.
Answer: 3.1 gallons
4.A fungicide, Nopatho 50 WP, is recommended at a 2 oz per
1,000 sq. ft. rate on the label. How much Nopatho fungicide
is needed to treat 1.75 acres?
Answer: 9.5 lbs
CALIBRATION
EXERCISES
APRIL 25, 2005
CALIBRATION
The process by which one determines the
application rate (gallons per acre or pounds
per acre) of equipment under a given set
of conditions.
APPLICATION EQUIPMENT
Multipurpose Sprayers : Hand Held Units,
Airblast Sprayers, and Spray Booms
Broadcast Applicators for Granular
Formulations
Band or Row Applicators for Granular
Formulations
Soil Fumigation Equipment
Injection and Implantation Equipment for
Trees
Greenhouse Applicators Can Range From
Mists, Dusters, Drenches, to Foliar Spray
Applicators
APPLICATION EQUIPMENT
Each Commodity Has a Separate
Write Up in the Commodity Manuals
Agricultural Manual : 10-15
Ornamental and Turf Manual:
Nursery and Landscape: 24-32
Turf : 40-43
Greenhouse: 51
WHY IS IT IMPORTANT TO
CALIBRATE?
Damage was due to poor nozzle distribution.
Sprayer nozzles set too low thus
causing a streaking effect.
SPRAYER CALIBRATION
FOUR VARIABLES THAT ONE CAN
ADJUST TO GOVERN SPRAY
OUTPUT ARE :
1) NOZZLE TYPE
2) NOZZLE SPACING
3) SPRAYER SPEED
4) SPRAYER PRESSURE
CONSIDERATIONS IN NOZZLE
SELECTION
Spray Product
Catalogs Will Provide
Important
Information In
Nozzle Selection
Nozzle Construction
Nozzle Pattern
Nozzle Spacing And
Height Above Ground
Nozzle
Screen Which Is Placed Before
Nozzle to Prevent Plugging of Nozzle
Example of
Catalog
Information
on Nozzle
Selection
CATALOG INFORMATION &
INTERPRETATION
65 Degree
Nozzle
80 Degree
Nozzle
110 Degree
Nozzle
Screen
Mesh
Size
Table Interpretation: For nozzle model 650067-SS it
has the following characteristics : It is a 65 degree nozzle
and can be used between 30 and 60 psi. If used at 50 psi
it’s output would be .07 gallons per minute (GPM).
Also at a 20 inch spacing and traveling
at 5 MPH the application rate would be 4.5 gallons per
acre (GPA).
PRODUCT CATALOG
INTERPRETATION
Based on the previous slide answer the following questions:
1. What would be the GPM of nozzle model 8001-SS if used
at 40 psi?
Answer: .1 GPM
2. If this nozzle is placed at a 20 inch spacing and a sprayer
travels at 6 MPH what will its GPA be?
Answer : 5.0 GPA
CATALOG INFORMATION
The height of the nozzle above the spray boom is important so as
to ensure uniform application. The table below shows the
recommended height for different spray nozzles spaced at 20” to 40”.
NOZZLE HEIGHT
NOZZLE TYPE SPRAY
20”
ANGLE Spacing
30”
Spacing
40”
Spacing
NOZZLE CONSTRUCTION
Brass
Polymer
Stainless Steel
Hardened Stainless Steel
Ceramic
Nozzles will wear differently based on their construction .
Refer to the following slide on wear differences.
Ceramic
H. St. Steel
St. Steel
Polymer
Brass
0
2
4
6
8
10
12
% INCREASE IN FLOW RATE AFTER 40 HOURS
Brass nozzles wear much quicker than other types of nozzles.
The ceramic nozzle wears the least.
This Sprayer Distribution Pattern
Shows Good Coverage Across The Boom
This Spray Pattern Shows Worn Nozzles ;
Greater Spray Under Each Tip Will Occur
NOZZLE PATTERN
Not every nozzle is created equal !
!
MAJOR TYPES
1)Standard Flat Fan
2)Extended-Range Flat Fan
3)Even Flat Fan
4)Twin Flat Fan
5)Flooding Fan Nozzles
6)Full Cone
FLAT FAN NOZZLE
Jack of all trades
Operating Pressure :
30 - 60 psi
Available in 65 , 80,
and 110 degree
angles
Overlapping is
required for uniform
application
A preferred nozzle
for herbicide
EXTENDED-RANGE
FLAT FAN NOZZLE
Similar to Flat Fan
but with wider
pressure range.
15-60 psi.
EVEN - FLAT FAN NOZZLE
Applies uniform
amount across its
spray width
Used in band
applications
Pressure
requirement of 2040 psi and
available in 40 or
60 degree spray
TWIN-FLAT FAN NOZZLE
Nozzle will have
two openings ; 60
degree separation
Increases
penetration into
crop canopy
30 to 60 psi
FULL CONE NOZZLE
Best for pre-plant
incorporated herbicides at
the 15-25 psi range. Low
pressure and large droplet
size will reduce drift
This cone nozzle is used
for high volume applications
40 inch spacing and nozzles
need to be angled at 30 to
45 degrees from vertical to
increase uniformity
HOLLOW CONE NOZZLE
Best suited for
Postemergence
herbicides. Can also
do well for placement
of insecticides, etc.
Fits well into low
volume applications
Drop nozzle
applications / 40-60
psi
FLOODING FAN NOZZLE
“FLOODJET”
Create a wide deflector type flat
spray pattern
Larger orifice reduces clogging
10-40 psi range / 40” spacing
SPRAYER SPEED
Inverse relationship between speed
and application rate
As speed increases application rate
decreases
To determine mph use the following
formula :
MPH = Distance Traveled (ft) x
60
Time
(sec.) x 88
SAMPLE PROBLEM
Determine the mph if a sprayer
travels 130 ft. in 40 seconds.
MPH =
130 x 60
40 x 88
MPH = 7800/3520 = 2.2 mph
CALIBRATION TECHNIQUES
There are numerous methods used
in calibrating sprayers. Several
different techniques and formulas
will be discussed in class
Calibration Tools
CALIBRATION:
Method 1
•Measure off known
area
Fill sprayer with water
to set level
Spray known area noting
pressure and speed
settings
Determine volume used
Set up an equality to
solve for your
application rate
CALIBRATION: Method 1
Assume area measured off is 50 feet by 60 feet
50 x 60 = 3000 sq ft.
The volume used was 4 gallons then the equality
is as follows …
4 gallons = x gallons
3,000 sq. ft 43,560 sq. ft
X = 58 gallons per acre (GPA)
CALIBRATION
FORMULAS : Method 2
GPA = 5940 x GPM ( of nozzle)
MPH x NW (nozzle spacing
in inches)
GPA = 495 x GPM ( of sprayer)
MPH x BW ( boom width in feet)
Conversion Factors
CALIBRATION
While the
sprayer is
running
determine the
nozzle output or
boom output by
collecting the
spray and
measuring the
volume.
SAMPLE PROBLEM
Determine the GPA of a sprayer if given the following
information. The nozzle out put averages .25 GPM and they
are spaced at 30 inches. The sprayer will travel at 6 MPH.
Using this formula one can solve for GPA :
GPA = 5940 x GPM
MPH x NW
GPA = 5940 x .25
6 x 30
GPA = 8.25
SAMPLE PROBLEM
Determine the GPA of a sprayer given the following
information :
The sprayer has 8 nozzles and each nozzle averages .5 GPM.
The boom width is 12 feet and will be traveling at 4 MPH.
GPA = 495 x GPM
MPH x BW
GPA = 495 x 4
4 x 12
GPM is for the entire sprayer
(8 nozzles). Therefore multiply 8
times .5 to get the sprayer out put of
4 GPM
GPA = 41.3 or round off to 41
Farmer Calibration
On-Line at: http://annearundel.umd.edu/files/SprayerCalibration.doc
Farmer Calibration
Farmer Calibration
DRY BROADCAST
APPLICATION
Measure a Known Area
Weigh Product Before One Treats
the Area and Note Spreader
Setting
Reweigh After Application
Setup Equality
DRY BROADCAST
APPLICATION
How much Insecto 5G will be applied per
acre based on the following information
Spreader Setting L
Area for calibration is 50 ft by 80 ft :
80x50 = 4,000 sq. ft.
Amount of Insecto 5G placed in spreader
was 90 lbs
Area is treated and Insecto 5G is
reweighed at 85 lbs. Difference = 5 lbs
Set equality :
5 lbs = x
4,000 43,560
Solve for x : (4000) (x) = (5) x (43560)
X = 54.5 lbs will be applied per acre
COMPUTERIZATION
Sprayer Control Systems
Adjust Pressure and Speed to
Deliver Desirable GPA Rates
Pictures From Teejet Web Page