Unit 9. Application Equipment, Calibration, and Methods

Question 1

Give two important reasons why you must apply just the right amount of pesticide to the target site.

Answer 1

• Applying less than the label recommendation of pesticide will likely fail to control the target pest.
• Applying more than the label recommendation of pesticide is illegal and may cause damage or injuries.

Question 2

Why do we calibrate pesticide application equipment?

Answer 2

To ensure that the equipment applies the correct amount of pesticide uniformly to the target site.

Question 3

What do we call the pesticide application technique that involves applying pesticides uniformly to an entire area or field?

Answer 3

Broadcast application

Question 4

What do we call the pesticide application technique that involves applying pesticides in strips (usually between crop rows)?

Answer 4

Band application

Question 5

What do we call the pesticide application technique that involves applying pesticides to specific target pests while avoiding other nontarget organisms in the same area?

Answer 5

Spot application

Question 6

What do call a type of indoor pesticide application technique that involves placing small amounts of pesticide into tight places, such as along baseboards or in cabinets?

Answer 6

Crack and crevice

Question 7

A directed application involves precise application to a specific area or site (ex. underleaf, fence line or guardrail spraying), often using specialized equipment.

What are some common specialized application devices that allow you to make directed applications?

Answer 7

1. An aerosol can.
2. A shield on a spray wand or boom.
3. An injector (ex. soil injector).
4. A wick or sponge wiper.

Question 8

Name at least four (4) parts of a sprayer.

Answer 8

1. Tank
2. Pump
3. Agitator (optional)
4. Hose(s)
5. Screens and filters
6. Pressure regulator (optional)
7. Boom or wand
8. Nozzle(s)

Question 9

What is the most important consideration when choosing a spray nozzle?
1. The target application rate.
2. The optimal spray droplet size.
3. The spray pattern (ex. fan vs. cone).
4. The intended spray pressure.
5. The chemical characteristics of your spray solution (ex. is it corrosive?).
6. All of the above.

Answer 9

6. All of the above.

Since the nozzle you select affects output, droplet formation and size, droplet distribution and spray pattern, you should consider all of these when choosing a spray nozzle.

In addition, different nozzles are designed for a range of spray pressures, resistance to chemical attack (ex. steel vs stainless steel), etc.

Choose your nozzle based on its design, spray pattern, orifice size, and operating pressure.

Question 10

Name the four (4) parts of a complete nozzle assembly.

Answer 10

1. Nozzle body.
2. Cap.
3. Screen.
4. Nozzle or orifice plate.

Question 11

What type of spray nozzle is used for broadcast applications with a spray boom?

Answer 11

Flat fan

Question 12

What kind of nozzle is well-suited to applying insecticides and fungicides to leaf surfaces?

Answer 12

Cone

Question 13

What type of sprayer would you typically use to spot treat weeds in a bed of ornamental plants?

Answer 13

A hand-held or backpack sprayer, preferably fitted with a spray shield around the spray tip. The shield will help prevent injury to ornamental plants by directing the spray to the target weeds.

Question 14

What kind of sprayer would you choose to make a broadcast application to a 25-acre field?

Answer 14

A boom sprayer (trailer or 3pt hitch-mounted).

Question 15

What makes a trailer or 3pt hitch mounted, low-pressure boom sprayer so versatile (useful)?

Answer 15

1. With the proper nozzle configuration, it is suitable for both broadcast and band applications.
2. Can be used to spray a broad range of insecticides, herbicides, fungicides, etc.
3. When properly configured and calibrated, it will evenly distribute pesticides over the target area.
4. Can be fitted with a hose and handgun for spot treatments and hard-to-reach areas.

Question 16

What type of sprayer would be best for covering a large area on steeply sloping ground or along a fencerow?

Answer 16

A boomless sprayer

Question 17

What kind of sprayer would you need to treat the dense foliage in tall trees?

Answer 17

A high-pressure tree sprayer.

Question 18

Briefly, what are the pros and cons of a high-pressure, power-driven sprayer?

Answer 18

Pros:
* Spray can penetrate dense foliage, thick animal hair, the tops of tall trees.
* Can deliver large amounts of spray quickly (up to 60 gallons per minute).

Cons:
* Expensive to buy and maintain.
* Use large amounts of gasoline or diesel to power them.
* High pressure increases likelihood of spray drift.

Question 19

What are the pros and cons of hand-held and backpack sprayers?

Answer 19

Pros:
* Low cost, simple to operate, easy to repair.
* Easy to clean and store.
* Useful in structures, spot treatment and hard-to-reach places.
* Some backpack sprayers have agitation, useful when applying suspensions.

Cons:
* Pressure and output fluctuate unless fitted with a constant-flow valve.
* Low pressure not suited for penetrating dense foliage or reaching much above 10 feet.
* Not suited to broadcast treatments (spot treatments only).
* Those lacking agitation do not handle suspensions well.

Question 20

Small-engine driven trailer- or skid-mounted sprayers can be fitted with medium-pressure pumps (up to 300 PSI), tanks up to 300 gallons in size, and booms or hand-guns. What are these sprayers used for?

Answer 20

1. Spraying fruit (grapes, berries) or small orchards.
2. Smaller ornamental trees to 30 feet tall.
3. Treating lawns and such where spraying with a boom sprayer or backpack sprayer is not practical.
4. Most have hydraulic agitation (poly tanks) or mechanical agitation (steel tanks) making them a good choice for spraying suspensions (ex. Wettable Powders (WP)).

Question 21

Could you use a granular formulation to treat a leaf surface? Explain why or why not.

Answer 21

Granules are not suitable for treating leaf surfaces because they will not stick to the target. Granules are better suited for soil applications.

Question 22

What are the pros and cons of using spreaders?

Answer 22

Pros:
* Easy to clean, maintain and repair.
* Designed to apply ready-to-use (RTU) products where no mixing is necessary.
* Applicator exposure and drift hazards are low.

Cons:
* Because granules and pellets do not stick to leaves or uneven surfaces, they are not suitable for some sites.
* Must recalibrate spreader for each granular formulation.
* Calibration requires catching and weighing the product applied to a test course.
* Uniform coverage can sometimes be challenging, especially with a rotary spreader.

Question 23

What is a wiper or wick applicator and how does it work?

Answer 23

• Use wiper or wick applicators to selectively apply herbicides to weeds.
• Particularly useful in pastures or row crops.
• Wicks made of rope, rollers made of carpet, or pads made of sponge or fabric are kept wet with a herbicide mixture and wiped directly onto weeds.
• Can be used to control tall weeds in shorter crops; or to treat weeds of any height between crop rows without concerns of drift.

Question 24

Why should you turn off your application equipment before you stop or come to the end of a row?

Answer 24

Because the equipment may continue to dispense pestcides even when you are not moving. When you are turning, the inside wheel gets heavy coverage, the outside wheel much less coverage (uneven coverage).

Question 25

List at least five (5) rules for proper use of pesticide application equipment.

Answer 25

1. Do not drive too fast for the equipment and the terrain.
2. Verify that the pesticide is reaching the target.
3. Calibrate your equipment if the label instructs you to apply a specified amount per unit area or volume.
4. Check equipment regularly (hoses, valves, nozzles, etc.) for signs of wear or failure. Check pumps and plumbing systems for leaks.
5. Be sure that equipment is dispensing product uniformly.
6. Shut off equipment when you turn or stop.
7. Make sure that no obstacle or machine part is interfering with pesticide distribution.
8. Keep equipment clean and free of debris.
9. Do not operate a sprayer with screens and filters removed.
10. Do not run a sprayer pump dry.
11. If you spray herbicides, dedicate one sprayer to herbicide applications. This will prevent unwanted damage to crops from herbicide residues.
12. Clean nozzles, screens, and suction filters with compressed air or a soft brush. Replace as needed.
13. Unplug a nozzle or spreader orifice using compressed air or soft brush.

Question 26

What is the best way to dispose of rinsate generated by cleaning your equipment?

Answer 26

Capture and use it for mixing a finished spray or apply to a legal site.

Question 27

What is the word for the process of measuring and adjusting the amount of pestcide applied by a piece of equipment, to a target area?

Answer 27

Calibration

Question 28

What are the four (4) reasons for calibrating equipment?

Answer 28

1. To make sure you are not exceeding the label rate.
2. To make the most effective pesticide application.
3. To protect human health, the environment and treated crops and surfaces.
4. Conserve resources (time, money, and the environment).

Question 29

When making a pesticide application, why is it important to make sure that all nozzles or hopper openings are releasing the same amount of pesticide?

Answer 29

To make the safest and most effective pestcide application you must ensure uniform delivery of product.

Question 30

What factors determine application rate?
1. Speed of travel.
2. System output in gallons per minute or pounds per acre.
3. Concentration of the pesticide in the mix or formulation.
4. All of the above.

Answer 30

4. All of the above.

1. The faster you travel, the less you apply per unit area.
2. The higher the system output, the more you apply per unit area.
3. The higher the concentration of pesticide, the more you apply per unit area.

Question 31

When calibrating a sprayer, what four (4) things can you change to ensure that you are applying the correct amount of pesticide?

Answer 31

1. Change the dilution rate.
2. Change the nozzle size (orifice size).
3. Change the spray pressure.
4. Change the travel speed.

Question 32

You plan to treat several areas measuring 1,000 ft², using a 4ft. drop spreader. You set up a 50-ft linear course to calibrate the spreader.
1. What is the area of the test course?
2. Is this test area the right size?

Answer 32

1. The area of the test course is 4 ft. x 50 ft. = 200 ft².
2. Yes, an area of 200 ft² is an appropriate size for calibrating small equipment, small loads, or small sites (less than an acre or 1,000 linear feet).

Question 33

During calibration, a sprayer delivered 2 gal of water over a test area measuring 250 ft². Your target area is 1,000 ft². How much spray mixture will you need to treat the target area?

Answer 33

2 gal x 1,000 ft²/250 ft²
= 2 gal x 4
= 8 gal

Question 34

Our target application rate is 25 gal/Ac. After spraying, we find that we actually applied 24 gal/Ac. Is this acceptable?

Answer 34

Yes.

The acceptable variation is 10% (plus or minus 5%). In this case, 5% of 25 gal/Ac is 1.25 gal/Ac. Therefore, the acceptable range of output is 23.75 gal/Ac to 26.25 gal/Ac. Since 24 gal/Ac falls between 23.75 and 26.25, you are within the acceptable margin of error.

Question 35

How does spray pressure affect flow rate?

Answer 35

• Increasing pressure will increase the flow rate.
• Decreasing pressure will decrease the flow rate.

Note that doubling pressure DOES NOT double the flow rate. You must increase pressure 4 times to double the flow rate. Since increasing the pressure by 4 times is usually not practical, we SHOULD NOT try and adjust the pressure regulator to make large changes in spray output. You may be able to make small changes to spray output by increasing or decreasing the spray pressure.

Question 36

How does travel speed affect flow rate?

Answer 36

• Increasing travel speed will decrease flow rate.
• Decreasing travel speed will increase flow rate.

In other words, the slower you travel, the more you apply per unit area. For example, doubling the travel speed will cut the flow rate by half. Cutting travel speed by half will double the flow rate.

Question 37

When calibrating a boom sprayer, what two factors should you check to ensure that all nozzles on the boom are working properly?

Answer 37

1. Pressure at the nozzles. Typically, you would mount a pressure gauge close to nozzles and compare that reading with the reading on the pressure-regulating valve.
2. Flow rate at the nozzles. Catch the output of each nozzle and measure the amount that you collect in one minute; or record the time needed to fill a one-quart pitcher (ex. 1 quart in 15 seconds = 1 gal/min).

Replace any nozzle that deviates from the rated flow rate by more than 5%.

Question 38

Spray output must be uniform along the length of the boom. Describe how to check the distribution pattern of the boom.

Answer 38

1. Use a pattern check tray or park the tractor on a level, dry piece of pavement.
2. Fill the spray tank with diluent (ex. water) and run the sprayer for a few seconds.
3. Check the spray pattern at each nozzle and check for proper overlap or band pattern. Flat fan nozzles should display proper overlap. Banding nozzles should leave dry areas between banding nozzles.
4. Check to see how water puddles under each nozzle. Areas that receive more liquid will dry more slowly.

Question 39

How do you measure the effective swath width of a boomless sprayer?

Answer 39

1. You spray water onto a dry surface under calm conditions at the operating pressure and spray height that you intend to use during product application.
2. Measure the width of the wet area. The completely wet portion is the effective swath width. When applying product, you want to match this width as closely as you can without gaps or overlap.

Question 40

The tank of your calibrated backpack sprayer holds 4 gallons. Your sprayer applies 2 gallons to 250 ft². Your treatment area is 1,000 ft². Can you treat the entire area with one tank?

Answer 40

No.
To treat 1,000 ft² you would need 2 gal x 1,000 ft²/250 ft²
= 2 gal x 4
= 8 gal
This requires TWO tanks (2 x 4 gal/tank).

Question 41

hint: in the previous problem, treating the entire area took 8 gallons.

In the previous problem, if the label rate is 4 oz. of product per gallon, how much pesticide would you need to treat the entire area?

Answer 41

4 oz x 8 gal = 32 oz (1 quart).

Question 42

When calibrating a sprayer or spreader, the test site should be proportional to the size of the treatment site. What is a good “rule-of-thumb” for choosing the size of a test site?

Answer 42

• If you are using application equipment that carries a small load (up to a few gallons of liquid or a few pounds of dry pesticide); or if the treatment site is small (less than 1 ac or 1,000 linear ft), mark off a test site that is 200 to 250 ft² or 100 linear ft.
• If you are using application equipment that carries a large load; or if the treatment site is large (more than 1 ac or 1,000 linear ft), mark off a test site that is at least 1,000 ft².

Question 43

What is the “ounce method” of boom sprayer calibration?

Answer 43

It is a quick and easy method to check and adjust a sprayer’s output.

1. Use a table (page 9-25 in the manual) of nozzle spacings to give you a test course length.
2. Fill the spray tank half full, get a running start and travel the test course while recording the elapsed time in seconds.
3. Park the sprayer and run it for the time required to drive the test course (ex. 25 sec), catching the output of one nozzle (broadcast) or all nozzles per row (banded or directed).
4. Output in oz = gallons per acre applied.

Question 44

What are the two (2) types of spreaders?

Answer 44

1. Drop spreaders that use gravity or an auger to feed product through an adjustable gate at the bottom of a hopper. Usually ground-driven.
2. Rotary spreaders that use a spinning disk to sling product out in a roughly circular pattern. Can be ground- or PTO-driven.

Question 45

How should a lawn care applicator using a granular product treat a yard to make the most even application?

Answer 45

By making two (2) passes, perpendicular (at right angles) to one another and applying half of the product in each pass.

Question 46

What are some of the ways in which dry pesticide formulations can vary?

Answer 46

Granules and pellets can very in particle shape, size, texture, and carrier composition.

All of these affect how particles move through the spreader’s hopper and openings. In addition, humidity can affect particle size and weight (ex. increasing particle size or causing clumping). Therefore, you must calibrate your equipment for each batch of product and changing field conditions.

Question 47

You plan to mark off a test course measuring 200 ft² to calibrate a 4-foot drop spreader. How long should this test course be?

Answer 47

50 feet. The spreader swath width is 4 ft.
200 ft²/4 ft = 50 ft.

Question 48

You need to apply a 2G (2% granule) product at a rate of 200 lbs per acre. How much active ingredient (a.i.) will you apply per acre?

Answer 48

A product with 2% a.i. contains 2 lbs of a.i. per 100 lbs of product. Therefore, if you are applying 200 lbs per acre, you are applying double that or 4 lbs. of a.i. per acre.

Question 49

Why is drift management so important?

Answer 49

Drifting pesticides may …
* Damage sensitive areas.
* Harm nontarget organisms.
* Leave illegal residues on crops.
* Violate state and federal laws.
* Waste money because your expensive pesticide is blowing away in the wind.

Question 50

Name factors that can increase spray drift.

Answer 50

1. Small droplet size.
2. Nozzles that create a small droplet (especially at higher pressures).
3. Spraying too high above crop or ground surface.
4. Operating speed that is too high.
5. Higher wind speeds.
6. High air temperatures.
7. Low relative humidity.
8. Thermal inversion (warm air above prevents air from rising upward).
9. Using low dilution rates of product (potential for larger percentage of product to move offsite.
10. Properties of the active ingredient.
11. Properties of the finished spray mix (especially volatile diluents).
12. Site characteristics such as windbreaks, buildings, etc. which affect wind speed and direction.

Question 51

Which droplet size usually provides better coverage: large or small?

Answer 51

Small droplets usually do a more thorough job of coverage. When complete coverage is an issue (ex. when spraying fungicides) we have to compromise between the need for coverage and the need to avoid spray drift. Consult the label for guidance on the ideal range of spray droplet sizes.

Question 52

List techniques that help minimize damage from spray drift.

Answer 52

1. Adjust sprayer pressure downward so that you form the largest droplets that still provide good coverage.
2. Choose a nozzle that is designed to reduce drift (ex. one of the newer “air induction” nozzles).
3. Position nozzles on the boom according to manufacturer’s recommendations.
4. Use drift-reduction hardware when practical (ex. spray hoods).
5. Use as low a spray release height as possible.
6. Keep tractor speed down.
7. Work when winds are light (3 - 5 mph) and steady. Avoid application when wind speeds exceed 10 mph.
8. Spray when wind is blowing away from sensitive areas.
9. Avoid spraying on hot, dry days.
10. Do not spray when the air is stagnant or when there is a temperature inversion.
11. Avoid using volatile active ingredients and diluents.
12. Use drift-control additives if appropriate.
13. Choose a formulation or application method that minimizes the chances of drift – especially around sensitive areas.
14. Maintain untreated buffer zones around treatment areas and nontarget sites.
15. Read all label directions carefully and follow them.