Calculation of Dosages

7/27/2019 Calculation of Dosages

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Calculation ofdosages

Pest Exterminators

Course

Pesticides Control Board

Conference Room

Central Farm

August 25, 2011

By Nonato Canto


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Calculation of dosages

Failure to use the correct dose (over orunder dose) will result in:

Development of pest resistance

Inadequate control of pests

Innecessary contamination of the environment


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Factors that could affect dosification:

Type of pest Nozzle type

Application method


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Conversion Factors

1 ml = 1cc

1 fluid ounce = 30 ml

1000 ml = 1 liter

1 gallon = 3.785 liters

1 gallon = 8.34 lbs

1 ounce = 28.4 grams

1 pound = 454 grams

1 kg = 1000 grams

1 kg = 2.2 lbs


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1) To determine the amount of pesticiderequired to treat an area at the requiredstrenght


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A) Determine the amount of pesticide required totreat an area at the required strenght.

Amount of

product needed=

Strenght of the spray in %

-----------------------------------

Strenght of the product in %

X

Totalquantity

of spray

required

Eg. How much Malathion 57 EC should be mixed with 10 gallons of water to

give a spray solution of 0.02%?


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A) How much Malathion 57 EC should be mixed with 10 gallons of waterto give a spray solution of 0.02%?

.

Amount of

product needed=


-----------------------------------


X

Total

quantity

of spray

required

0.02%

? = ----------------------------------- X 10 gallons

57 %

= 0.004 gals x 3.785 = 0.015 lts

= 0.015 lts x 1000 = 15 cc

= 0.004 gals


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A) How much Gramoxone 20 SL should be mixed with 5 gallons of water to

give a spray solution of 1%?

.

Amount of

product needed=


-----------------------------------


X

Total

quantity

of spray

required

1%

? = ----------------------------------- X 5 gallons

20 %

= 0.25 gals x 3.785 = 0.015 lts

= 0.946 lts x 1000 = 946 cc

= 0.25 gals


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A) Calculate the amount of Permethrin 8 EC

required to make 15 liters of 0.003% spray solution.

Amount of

product needed=


-----------------------------------


X

Total

quantity

of spray

required

0.003%

? = ----------------------------------- X 15 liters

8 %

= 0.0056 lts

= 0.0056 lts x 1000 = 5.6 cc


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A) Calculate the amount of Diazinon 40 EC required

to make 60 gallons of 0.05% spray solution.

0.05%

? = ----------------------------------- X 60 gallons

40 %

= 0.075 gals

= 0.075 gals x 3.785 lts = 0.283

= 0.283 liters x 1000 = 283.87 cc


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A) Mr. Ted was contracted to do a pest extermination job at Princess Hotel. Heinspected the premises and decided to use Dursban 24 EC for the control of a heavy

infestation of ants and roaches. He calculated that it will take 100 liters of water to

cover the entire area using a spray solution of 5%. How much Dursban 24 EC will

he need?

0.5%

? = ----------------------------------- X 100 liters

24%

= 2.08 lts


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Calculation of Dosages

To obtain the spray concentration in % when a known

quantity of chemical is added to a known quantity of water

---------------------------------------------------Spray

Concentration=

Concentration of

the product (%)

Quantity of

product Used

Quantity of spraysolution required

x


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---------------------------------------------------

SprayConcentration

=

Concentration of

the product (%)

Quantity of

product Used

Quantity of spray

solution required

x

Eg. What is the spray concentration when

400 cc of Malathion 50 EC is added to

1000 liters of water?

50% x 0.4

? = --------------------- = 0.02%

1000 liters


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500 cc of Regent 20 EC is added to 200

liters of water?

20% x 0.5

? = --------------------- = 0.05%

200 liters


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150 cc of Proquat 20 SL is added to 20

liters of water?

20% x 0.150

? = --------------------- = 0.15%

20 liters


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150 cc of 2,4 -D 60 SL is added to 20

liters of water?

60% x 0.15

? = --------------------- = 0.45%

20 liters


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175 cc of 2,4 -D 60 SL is added to 16

liters of water?

60% x 0.175

? = --------------------- = 0.65%

16 liters


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A farmer has been advised to spray his watermelon field with Malathion

50 EC to control Aphids. The recommended rate is 1.5 lts per acre. His

field measures 223 ft x 144 ft. . Using a knapsack sprayer with 4 gallons,

he can cover the area with 6 tankfulls. How much Malathion is needed?

How much should he add per tankfull ?

1) Find the area of the field.

Area = 223 ft x 144 ft = 32, 830 square feet

Since 1 acre has 43, 560 square feet, this field

measures :

32, 830 sq ft

____________ = 0.75 acre in size.43. 560 sq ft


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2) Find the amount of Malathion 50 EC that is needed to

treat the required area. (0.75 Acre)

If 1.5 lts is required for 2.5 ha., then 0.75 acres

will be

1500 cc = 2.5 acre.

? = 0.75 acre

1500 cc x 0.75 acre

____________ = 450 cc

2.5 acre


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3) Determine the amount of Malathion 50 EC needed per

knapsack?

If 450 cc needed for 6 tankful, 1 tankfull will be

450 cc = 6 tankfull

? = 1 tankfull

450 cc x 1 tankfull

____________ = 75 cc /tank

6 tankfull


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Calculation of Dosages