Casey Reynolds
NCSU Turfgrass Research Associate
 Topics included in this discussion:
 The importance of sprayer/spreader calibration with
regard to cost control
 Interpretation of pesticide labels
 How to calculate rates and costs of:
 Liquid and granular formulations for spraying
 Granular applications of fertilizer and pesticides
 Combination products (fertilizer and pre-emergence)
 Cost analysis of turfgrass management programs
 Why is sprayer/spreader calibration important?
Plant Health Products:
 Achieve the recommended application rate to meet
plant needs and/or control target pests (weeds,
insects, diseases)
 Avoid injury of desired turfgrasses
 Maintain Environmental Responsibility
 Control COSTS!
 Example problems:
 How much would an application of Barricade 65WDG
cost for an 8,000 sq ft home lawn if the labeled rate is
1 lb ai/acre and Barricade 65WDG is $39.95/lb?
 How much would an application of (granular
combination product) cost for the same lawn, at the
same rate?
 What information do we need to answer these types
of questions?
 Product formulation (WDG, FL, G, etc..)
 Recommended application rate
 Acreage/sq ft of area receiving application
 Product cost $$$
 What tools do we need to make an accurate
application?
 Calculator/Pen/Paper
 Properly calibrated sprayer and/or spreader
 Calibration equations
 Access to pesticide labels
 Pest control recommendation guide
 www.turffiles.ncsu.edu
 www.cdms.net
 www.greenbook.net
 First and foremost, proper label interpretation and
sprayer calibration is important for what reason?
 To avoid injury to desired turfgrasses and non-target
plants/organisms
Roundup injury on
Zoysiagrass
What‟s wrong with
this application?
 What happened here?
 So, how do we avoid these types of situations???
 Through two steps:
 Step 1: Label Interpretation
 Step 2: Sprayer Calibration
 What types of information can we extract from
pesticide labels?
 Formulations
 Active ingredient
 PPE (Personal Protective Equipment)
 Proper Storage and Handling
 Precautions/Recommendations
 Timing
 Rates
 Spray Volumes
 Mixing
 Etc..
 Why is it important to know the product formulation?
 Preference of applicator (Liquid or Solid)
 Calibration and Calculation of rates
 Cost analysis
 Formulations
 Several common formulations of pre-emergence
herbicides for crabgrass
 Pendulum 60WDG
 Barricade 4FL
 Dimension EC
 Barricade 65WDG
 What do these mean???
 Let‟s break this down:
Pendulum 60 WG
Common name
Concentration
(for chemical name)
(of active ingredient)
Formulation
(Liquid/Solid)
 Formulations
 Represent the active ingredient in the product as well
as whether it is a liquid or a solid.
Liquid Formulations
 Liquid (L), Flowable, (F or FL), Emulsifiable Concentrate
(EC), Sprayable (S), Soluble Liquid (SL), etc…
Dry Formulations
 Water Dispersable Granule (WG or WDG), Wettable Powder
(WP), Water Soluble Powder (WSP), Pellet (P), Granule (G),
etc…
Calculating Rates of Dry Formulations
 When using dry formulations the number on the label
refers to % active ingredient by weight..
Example:
Barricade 65 WDG is 65% by weight prodiamine (ai)
 Therefore:
 100 lbs of Barricade 65 WDG contains 65 lbs of prodiamine
 1 lb Barricade 65WDG contains .65 lbs of prodiamine
Calculating Rates of Liquid Formulations
 When using liquid formulations the number on the label
refers to lbs of active ingredient per gallon of product
Example:
Barricade 4FL has 4 lbs prodiamine (ai) per 1 gallon of product
 Therefore if you have a 2.5 gallon jug of Barricade 4FL you have 10
lbs prodiamine.
4 lbs ai x 2.5 gallons = 10 lbs ai
1 gallon
 So, how do we incorporate this information into
sprayer/spreader cost calculations?
 Through Dimensional Analysis!
Start with what you have, to get to what you want !
Start with what you have, to get to what you want !
Simple, random example:
 How much would 5 truckloads of drinks (pepsi, coke,
etc.) costs when delivered to a convenience store if there
are one thousand, 20 oz drinks per truck and they cost
$0.05 /oz?
Have
Truckloads
Want
Cost $$
Beginning with the unit you have, proceed to the unit you
want by “cancelling out” units through multiplication.
5 truckloads 1,000 drinks 20 oz $0.05 =
truckload
drink 1 oz
Have
Truckloads
Want
Cost $$
5 truckloads 1,000 drinks 20 oz $0.05 = $5,000
truckload
drink 1 oz
Or, look at it this way:
(5 truckloads) (1,000 drinks) (20 oz) ($ 0.05) = $5,000
(truckload) (drink) (oz)
*Units disappear when divided by similar units leaving only the unit of
interest left at the end.
Example Problem in turfgrass:
 How much would an application of Barricade 65WDG
cost for an 8,000 sq ft home lawn if the labeled rate is 1
lb ai/acre and Barricade 65WDG is $39.95/lb?
 Start with what you have, to get to what you want !
Have
8,000 sq ft lawn
Want
Cost $$
8,000 ft2 lawn 1 acre
1 lb ai 1 lb Barricade $39.95 = 319,600
43,560 ft2 1 acre 0.65 lbs ai
1 lb Barr
28,314
= $11.28
Therefore, for an 8,000 ft2 lawn the total product cost
for this application of Barricade 65 WDG would be $11.28.
 If tank-mixed with a 3-way combination product for
broadleaf weed control, how much would broadleaf weed
control add to the cost?
 Ex: Trimec class at $29.50/gallon?
Have
Want
8,000 ft2 1.25 oz Trimec 1 gallon $29.50 = $2.30
1,000 ft2
128 oz 1 gallon
 How much would a spring fertilization cost for the same
lawn if using 28-5-12 at 1 lb N/1000 ft2. The fertilizer cost
$12.50 per 50 lb bag?
N-P-K analysis (by weight)
28% Nitrogen
5% Phosphorous
12% Potassium
* 28 lbs N, 5 lb P, and 12 lbs K
per 100 lbs fertilizer
28-5-12 at 1 lb N/1000 ft2
8,000 ft2 1 lb N
1 lb fertilizer $12.50 = $7.14
1,000 ft2 0.28 lbs N 50 lbs fert
Combination Products
 Fertilizer is often combined with pre-emergence
herbicides for ease of application.
 When this is done, how does this affect calculation of
rates and cost?
Combination Products
 If applying a 19-0-6 granular fertilizer with 0.38%
barricade what is the rate of fertilizer in lbs N/1000 ft2 and
Barricade in lbs ai/acre if using the labeled product rate
of 265 lbs/acre?
 You can calculate the fertilizer rate or chemical rate first,
 Let‟s start with the fertilizer rate in this example.
Have
265 lbs fert
1 Acre
Want
0.19 lbs N 1 acre
1000 = 1.15 lbs N
1 lb fert
43,560 ft2
1000 ft2
All units cancel except lbs N/ft2.
Multiply by 1000 to get lbs N/1000 ft2.
 Now, the chemical rate.
Have
265 lbs fert
1 Acre
Want
0.0038 lbs ai = 1.007 lbs ai/acre
1 lb fert
Combining these calculations with other resources allows
you to calculate more specific desired rates for each
application.
Ex: 0.75 vs. 1 lbs ai/acre Barricade
 These types of calculations also allow you to assess
where your $$ is going and which applications are
more/less expensive than others.
 Product costs „relative‟ to each other can be
expressed on a 1000 ft2 or acre basis.
Area
1000 ft2
or acres
Rate
Analysis
Cost
oz/acre,
lbs/1000
ft2, etc.
lbs ai, lbs
nutrient,
etc.
$/lb,
$/gall,
etc.
By plugging in the appropriate information for each component, you can
easily and quickly calculate product costs for comparison.
Granular Fertilizer
30-6-10 w/ 50% SCU
18-24-12 w 50% SCU
Price
lbs N / 1000 ft2 Cost / 1000 ft2
$12.32 / 40lbs 1
$1.02
$13.50 / 50 lbs 1
$1.50
Cost / Acre
$44.43
$65.34
Pre-emergence Products
Barricade 65WG
Barricade 65WG
Dimension EC
Dimension Ultra 40 WP
Pendulum 3.3EC
Pendulum 60 WDG
Price
$38.95 / lb
$38.95 / lb
$116.5 / gal
$53.08 / lb
$36.95 / gal
$9.51 / lb
lbs ai / acre
1 lb
0.75 lbs
0.5 lbs
0.5 lbs
3 lbs
3 lbs
Cost / 1000 ft2
$1.37
$1.02
$1.33
$1.52
$0.77
$1.09
Cost / Acre
$59.68
$44.80
$58.25
$66.35
$33.54
$47.55
Combination Products
20-4-10 w/ 0.29 Barricade
16-4-8 w/ 0.38 Barricade
Price
$24.93
$21.88
lbs ai / acre
0.75 lbs
0.75 lbs
Cost / 1000 ft2
$2.82
$2.00
Cost / Acre
$123.08
$87.52
Broadleaf Products
Escalade 2
Speedzone 2.2EC
Trimec Classic
Price
$46.82 / gal
$55.19 / gal
$29.77 / gal
lbs ai / acre
1.25
1.25
1.25
Cost / 1000 ft2
$0.34
$0.53
$0.29
Cost / Acre
$15.00
$23.09
$12.63
Fungicides
Price
oz/ 1000 ft2
Cost / 1000 ft2
Cost / acre
Heritage
$400/lb
0.4
$4.56
$198
Granular Program
Visits Treatment
16-4-8 w/ 0.38
1
Barricade
Month
Description
February
Fert and Crabgrass
Cost / 1000 ft2
Cost / acre
$2.00
$87.52
$1.02
$44.43
TOTAL Spring Cost
$3.02
$131.95
Fall seeding
$3.80
$165
Fertilization
$1.50
$65.34
Winter fertilization
$1.02
$44.43
TOTAL Fall Cost
$6.32
$274.77
TOTAL YEARLY
COST
$9.34
$406.72
Pre-emergent
2
30-6-10 w/ 50% SCU
April
and micro package
3
Tall Fescue seed and
fertilization
Sept-Oct
18-24-12
4
30-6-10 w/ 50% SCU
Late spring
Nov-Dec
and micro package
Liquid Program
Visits Treatment
1
Proclipse 65WG
Escalade 2
46-0-0 Urea
2
14-2-14 w/ Micro and
60% Slow Release
3
14-2-14 w/ Micro and
60% Slow Release
4
5
Tall Fescue seed and
18-24-12
28-0-0 with 70%
Slow Release
Month
February
Description
Pre-emergent
March
Fertilization
April-May Fertilization
Sept-Oct
Nov-Dec
Cost / 1000 ft2
$0.73
$0.34
$0.44
$3.81
Cost / acre
$32.00
$15.00
$19.14
$165.74
$1.90
$82.65
TOTAL Spring Cost
Fall seeding
Fertilization
Fertilization
$7.22
$3.80
$1.50
$0.82
$314.53
$165
$65.34
$35.67
TOTAL Fall Cost
$6.12
$266.01
TOTAL YEARLY
COST
$13.34
$580.54
8,000 ft2 lawn $9.34
1,000 ft2
= $74.72 Total product cost/yr
for all granular program
$60 per visit x 4 visits = $240
Profit margin: $240 - $74.72 = $165.28
8,000 ft2 lawn $13.34
1,000 ft2
= $106.72 Total product cost/yr
for all liquid program
$60 per visit x 5 visits = $300
Profit margin: $300 - $106.72 = $193.28
Cost analysis of each program
 In this example, the liquid program is $28 more profitable
per year. However, it requires 1 extra visit.
 Things to consider:
 Liquid visits may be quicker allowing more visits per day.
 Customer preference towards more or less visits
 Image vs. cost
 Applicator preference
 Others….
Cost analysis of each program
 The point of ALL of this math is not to recommend liquid
vs. granular. In reality, a combination of both is often
desirable.
 The point is simply to take time to do the math in order to
see where your costs are going.
 This type of cost control in the office makes applications
more profitable without any additional labor in the field.
 In addition to comparisons BETWEEN products,
calculations are also important to control costs
WITHIN products.
 Most plant care products recommends RANGES of
application rates.
 For example, „Heritage‟ fungicide has a recommended
application rate 0.2 to 0.4 oz/1000 ft2 for brown patch
control in tall fescue.
 This may not sound like much, but at approximately $400
per lb it translates to a significant difference in cost.
 Again, let‟s take the previous example of our 8,000 ft2
lawn.
8,000 ft2 lawn 0.2 oz
1,000 ft2
1 lb
16 oz
$400
1 lb
= $40
At the higher rate of 0.4 oz, this doubles to $80 in product cost
for the lawn.
As one can imagine, it doesn‟t take many misapplications of
this product to quickly begin losing money.
 How do you determine what is the appropriate rate
when product labels provide ‘ranges’?
 NC Pest Control Recommendation Manual
 NCSU Turffiles website: www. Turffiles.ncsu.edu
 Previous experience and record-keeping
 ALL of this is COMPLETELY dependent upon having a
properly calibrated sprayer and spreader!!!
 Otherwise, calculations performed in the office will not
translate into savings in the field..
5940 Method: GPA and GPM Equations
 GPA = GPM x 5940 or GPM = GPA x MPH x NSI
MPH x NSI
5940
Where :
GPA= gallons per acre
GPM = gallons per minute
MPH = miles per hour
NSI = nozzle spacing in inches
1/128th Method: CALIBRATING a BACKPACK SPRAYER
1 Acre = 43,560 sq.ft.
1/128 Acre = 340 sq.ft.
1 Gallon = 128 ounces
Ounces sprayed to cover 340 sq.ft. = Gallons per acre
8 ft.
18.4 ft.
18.4 ft.
= 340 sq.ft. =
42.5 ft.
Spray an area 340 sq. ft. with
your backpack sprayer and use
a stopwatch to record the time.
Spray with your backpack sprayer into a bucket or
measuring container for the length of time needed to
cover 340 sq. ft.
The number of ounces collected equals the gallons per acre spray coverage using
your backpack sprayer.
Example: Time to spray = 15 seconds.
15 seconds collect 30 ounces of water.
30 ounces = 30 gallons per acre spray rate.
43,560sq.ft. / 30 gls. = 1452 sq.ft. per gallon.
4 gl. Backpack would cover 5805 sq.ft.
Spreader Calibration
 Granular product labels often provide starting points
for calibration based on spreader manufacturer.
 However, it is ALWAYS important to perform your own
calibrations using more accurate methods such as:
 Catch Pan Method
 Sweep and Weigh Method
Conclusions
 Spreader/sprayer math is very important in achieving
adequate control when using fertilizers and other plant
health products.
 As illustrated, it is also extremely important in controlling
costs and making profitable applications.
Conclusions
 It is important to use all of the tools at your disposal to
properly calculate materials and calibrate equipment.
 These include:
 NCSU Turffiles: www.turffiles.ncsu.edu
 Useful labeling websites: www.cdms.net
 NC Pest Control
Recommendation Guide
 Others…