pesticide application and calibration

8/6/2019 Pesticide Application and Calibration

http://slidepdf.com/reader/full/pesticide-application-and-calibration 1/41

PESTICIDE APPLICATIONAND CALIBRATION



Pesticides

Any chemical used to control pests (e.g. insecticides,

herbicides, rodenticides, fungicides)

Not usually applied in a pure form

It must be diluted with water, oil, or an inactive solid

so it is less toxic to humans and can be spread

evenly over a large area. The final product is

called pesticide formulation



Types of pesticide formulations

1. Dusts

� Pesticide + a finely ground dry particle such as

clay, talc, or volcanic ash

� Advantage ² require no mixing and can be

applied directly to a plant

� Disadvantage ² may drift long distances from

where they were applied, danger of beinginhaled




2. Granules

� Pesticide + dry particles of sand or other

materials which are larger than those used in dust

� Advantage ² can be applied with simple

equipment and require no additional mixing,

relatively non-toxic to applicators and do not drift

from target area� Disadvantage ² cannot be used to treat foliage

because they will no stick to it




3. Wettable powders

� Pesticide in powder form + wetting agent

� Advantage Easy to carry and store

Easily measured and mixed and are not absorbedeasily through skin

� Disadvantage May be toxic to the applicator if he inhales the

concentrated dust during mixture

Must be agitated periodically in the spray tank




4. Liquid formulations� Pesticide + organic solvent + emulsifier + spreaders

and stickers

� Advantage

Contains high concentration of pesticide so the priceper unit is low

Easy to transport and store Effective in treating foliage

Require little agitation in the tank to keep themmixed

� Disadvantage

Easy to underdose or overdose Dangerous to humans: can be absorbed through

the skin



Pesticide

Information on a pesticide labels1. Type of pesticide

2. Trade names

3. Net contents

4. Directions for use

5. Name and address of the chemical company

6. Hazard statement7. Common name or chemical name of the actual poison

(a.i.) and the percentage of the material in theformulation



Pesticide = A.I. + other compounds

a.i. = 25%, 50%, 60%, etc



Pesticide calculation

1. To control weeds, you were assigned to spray 1 kgof glyphosate in a 1 hectare corn field(recommended rate). You were given Herbicide X

to be used. The label says that the Herbicide Xcontains 50% a.i. (glyphosate). How much Herbicidex (in kg) are you going to use?

A. If Herbicide X contains 25% a.i.?

B. If herbicide contains 43% a.i.?

What is the formula? rr/% a.i.



Calculation of percent concentration

% concentration = volume or weight of active ingredient

vol or wt of water



Sample problem

You wish to apply 320 liters of spray solution/ha. Therecommended spray concentration of 45% a.i. is0.04%. How many liters of the commercial formulationare required in a 1 hectare field?

Given:

320 liters/ha; 45% a.i. ; 0.04% recommendedconcentration.

= vol of spray required x % recommended concentration

% a.i.



Factors affecting the choice of a pesticide

formulations

1.

Type of pests and their habits (weeds, rodents,insect or diseases)

2. Application equipment

3. Danger from drift and runoff

4. Advantages

5. Cost



Precautions in handling pesticides

1. Read the labels to determine:

1. Rates

2. Timing

3. Need for protective clothing or equipment

4. Antidotes and other pre-cautionary measures

5. Field re-entry intervals after treatment

6. Other safety measures2. Check the sprayer : make sure that there are no

leaks or loose connections and the equipment is

working properly




3. In mixing and filling sprayers

1. wear protective clothing

2. open pesticide containers carefully

3. Stand upwind when adding material to the sprayer to

avoid drift

4. Keep your head away from the opening of the

sprayer

5. Wash and change clothes immediately if spilled on

clothing

6. Do not mix pesticides with your hand




4. During application

1. Wear protective clothing

2. Avoid exposure

3. Do not eat, drink and smoke4. Spray with the wind

5. Avoid contamination of nontarget areas

6. Do not spray during high winds

7. Do not spray near or in ponds, lakes or streams8. Spray areas near homes in early morning or evening

when humans, pets and livestocks are less likely to beexposed




5. After application

1. Make sure that the sprayer is empty

2. Clean and rinse the inside and the outside of sprayer

and return to storage area

3. Store remaining pesticide properly

4. Bathe and change clothing

5.

Stay away from treated fields for 1-2 days



Application of chemicals with respect to area covered

1. Broadcast application ² application that covers an

entire area

2. Band application ² application in a continuous

restricted band such as in, or along a crop row

3. Spot treatment ² localized application



Types of sprayer

1. Compressed air sprayer



Types of sprayer

2. Tractor-mounted sprayer



Types of sprayer

3. Knapsack sprayer



Spray nozzle

Breaks up liquids into droplets and disperses these

droplets in a particular pattern

Different types of nozzles produce different droplet

patterns



Types of spray nozzles

1. Fan nozzles ² used mainly for applying herbicides,

can also be used for directed insecticide

applications



Types of spray nozzles

2. Cone nozzles ² give good coverage of plant leaf

and stem surfaces for control of insects and

diseases

Solid cone Hollow cone



Sprayer calibration

Calibrate ² adjust, standardize or regulate

Why calibrate the sprayer?

To make sure that you apply the right amount of

pesticide that can effectively control the target pest

You can properly estimate the time needed to spray

a known area



Sprayer calibration and pesticide

calculation

Materials needed in sprayer calibration

1. Measuring cup (graduated cylinder)

2. Tape measure or meter stick

3. Stopwatch

4. Sprayer




calculation

Data needed in calibration

1. Known area

2. Time spent spraying a known area

3. Amount of solution discharge in a known area



Showerhead Nozzles

Calibration

�Step 1: Mark off a test course at least 20

meters long and determine your swath width.

Calculate the area in square meter of your

test course.



Showerhead Nozzles

Calibration

�Step 2: Spray the test course with water

using the technique you will use during the

actual application. Always begin spraying

before entering the test course.



Showerhead Nozzles

Calibration

�Step 3: Record the number of seconds

required to spray the test course. Average 3

test applications together for accuracy.



Showerhead Nozzles

Calibration

�Step 4: Determine the volume of water

applied to the test course by spraying into a

cylinder for the number of seconds required

to cover the test course.



You must recalibrate when

you change from onematerial to another.



Ground speed must be consistent.

Doubling the ground speed does not

always double the application rate!




calculation

Questions to answers:

1. What is the volume discharge per hectare

2. How many tankloads can supply the requirement?

3. How much area can 1 tank load cover?

4. If the herbicide has 50% a.i.:

a. How much should you apply in a 1-hectare field if the

recommended rate is 0.8 liters a.i. /ha?b. How much pesticide should you put per tank?




calculation

Questions to answers:

5. If the recommended rate for herbicide application is0.5 kg a.i./ha, how much linuron (50% ai) is required?

6. Using the total volume discharge per area measuredin the experiment, how much (volume) solution shouldbe used in an area with 2 plots having an area of20sqm each?

7. How much time will it take for you to spray 1.5

hectare of field?8. From the experiment what are the factors that can

affect the calibration of sprayer.




calculation

1. You were asked to apply herbicide to a 2.5-hectare tomato

plantation. To manage your time and resources properly, you

calibrated the 16-liter sprayer and came up with the following data:

Average time spent to cover a 4m x 5m field = 36.9 secondsAverage volume of water discharged = 313 ml

Questions:

a) How much (in liters) are you going to spray in the entire

plantation?

b) Area that can be covered by one tankload.

c) How much time (in hours) do you need to spray the entire

plantation?



2. A farmer wants to know why Herbicide X, (containing

400g ai/liter product) a broad-spectrum preemergence

herbicide failed to provide adequate weed control when

applied in transplanted rice. The recommended rate of

application of the herbicide is 0.4 kg ai/hectare.According to the farmer he placed 60ml of Herbicide X

into each tankload and that one tankload of spray was

sufficient to cover 2 plots measuring 25m x 20m each.

Question (show proof):Indicate the most probable reason why the herbicide did not

perform as expected

pesticide application and calibration

Documents