Safe Use of Herbicides, Fungicides and Insecticides
Herbicides,
fungicides and insecticides are classified according to the use hazard and risk involved.
The categories of hazard are:
- toxicity
- flammability
- explosive potential
- corrosivity
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Table of Contents:
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The degree of risk is represented by symbols
taken from common traffic sign shapes represented by the stop,
caution and yield signs. The signal word for each of the signs is
danger, warning and caution. Where the risk is minimal, no
designation is required. The label on the container will carry the
appropriate signs for the protection of the user. Degree of risk
information for herbicides, insecticides and fungicides used in
fruit crops are summarized in tables entitled "Hazard Ratings and
Relative Toxicities" and located just prior to the product
descriptions. The symbols are illustrated in Figure 1.
LD50 values are used to rate the
toxicity of pesticides. The LD50 refers to the dose of
pesticide (in mg per kg of the test animal's body weight) that is
lethal to 50 percent of the group of test animals. For example, if a
pesticide has a LD50 value of 10 mg/kg, and the test
animals each weigh 1kg, then 50 percent of the animals would die if
they each ate 10 mg of the pesticide.
Oral LD50 values as they relate to the
Risk/Hazard Symbols: Different types of protective equipment are required for pesticides that differ in
toxicity. Special equipment requirements are described on the product label, but in
general the following precautions must be taken when using pesticides of different hazard
ratings.
Danger Poison - requires goggles,
respirator, gloves and skin protection, avoid fumes and spray mist.
Warning Poison - requires goggles, gloves and skin
protection, avoid fumes and spray mist.
Caution Poison - requires gloves and skin
protection, avoid fumes and spray mist.
The absence of a hazard symbol on a pesticide label indicates low toxicity to mammals.
Nevertheless, protective clothing should be worn when using pesticides that do not have a
hazard symbol. |
Click to expand
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Protecting Yourself from Exposure
The use of protective equipment and sound safety procedures will help minimize your
exposure to herbicides, insecticides and fungicides. Follow the 10 rules for safe
application listed, and wear the safety equipment recommended.
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10 Rules for Safe Application
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Never smoke or eat while applying pesticides.
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Avoid inhaling sprays or dusts. Wear protective clothing and a respirator.
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Sprayer lines carrying chemicals should not enter the operator's cab.
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Have soap, water and a towel available. Should concentrated product spill on skin,
hands, face or eyes, wash immediately.
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Wash hands and face when leaving the treated area, before break periods, lunch or
urination.
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Bathe or shower and change to clean clothing after working with pesticides. Wash
clothing each day before re-use.
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Call a physician or get the patient to a hospital immediately if symptoms of illness
occur during or shortly after pesticide application. Be sure to take along the product
label or container.
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Store pesticides out of reach of children and where there is no chance of contact with
human food or livestock feeds. Do not store herbicides with insecticides and avoid
cross-contamination. Storage areas should be locked.
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Keep chemicals in their original containers, never in unmarked containers or bottles
used for food or drink.
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Follow proper container disposal methods. All containers should be triple rinsed or
pressure rinsed, punctured to render the container non-reusable, and delivered to
designated disposal sites.
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Protective Clothing
Wear protective equipment as described in the chart to reduce exposure.
Equipment |
Protection |
How to Wear It |
Coveralls |
There are two types of coveralls: disposable and
reusable. Disposable coveralls are lightweight and comfortable on warm days. They can be
worn for mixing and applying pesticides, then discarded at the day's end. If they become
contaminated, they should be discarded at once.
The second type of coveralls is made of washable fabric and may be reused many times.
These fabric coveralls are adequate for use with all but the most highly toxic and
concentrated pesticides. |
Button (or zip) right up to the neck. Loose coveralls
around the neck will suck and blow pesticide in and out of the interior of the coveralls
as you bend and move.
Wear coveralls over a long-sleeved shirt and pants. |
Aprons |
When pouring or otherwise handling concentrated
pesticides, it makes good sense to wear protection in the form of an apron. The apron
protects the front of your body from spills or splashes of the concentrate. The apron
should be made of rubber or synthetic liquid-proof material that will resist the solvents
used in formulating the pesticide. |
Make sure the apron covers your body from your chest to
your boots. |
Gloves |
Protect your hands by wearing appropriate
chemical-resistant gloves. Be sure they are designed for use with solvents and pesticides.
Refer to the product label for specific recommendations on the type of personal protective
equipment required. Never use lined gloves, gloves with wristbands or leather gloves. |
Put gloves on and roll up the first inch or two of the
cuff. That way when you lift your hands, any liquid on the gloves won't drip down your
arm. |
Hats |
Use a chemical-resistant hat, preferably made of
washable plastic. The hat may be a hard hat, or it may be made of flexible plastic. In
either case, it should have a plastic sweatband. Wash and dry entire hat after each use
and before storing. Ordinary baseball caps with cloth sweatband are dangerous as they
absorb the pesticide and recontaminate the forehead each time you wear them. Even small
amounts of moderately or slightly toxic pesticides may cause severe skin irritation or
other illness if exposure continues for several days. |
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Boots |
Wear chemical-resistant, unlined boots. These boots are
available in a variety of styles and materials. Neoprene boots are the best. Knee-length
boots offer greater protection because they extend above the lower end of the apron. Avoid
leather or fabric boots and shoes because they will absorb pesticide and cannot be cleaned
effectively. |
Wear your pant legs outside the top of your boots. This
will prevent spills and splashes from running into the boot and on to your leg. |
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Protecting Your Eyes, Face and Lungs
Wear
the following equipment to protect your facial area from exposure.
Equipment |
Protection |
How
to Wear It |
Goggles |
Chemical-resistant goggles keep your eyes
safe from both splashing and, if using dry formulations, dust or granules. Don't use
goggles with cloth or elastic headbands as these will absorb pesticides. |
Wear goggles snugly on your face so that
the sides of your head are protected from splashes. If you wear glasses, make sure you
purchase goggles which fit snugly over them. Never wear contact lenses when working around
pesticides. |
Respirators |
Only NIOSH-approved respirators should be
used. Do not exchange parts of different respirators. (For example, do not use a cartridge
produced by Company "A" with a respirator produced by Company "B" as
the combination may not provide adequate protection to the user). Dust masks are
ineffective in protecting against herbicide vapors. Similarly, the filters on tractor cabs
are intended to remove dust and are not designed to protect against pesticide vapors or
mists. Chemical cartridge respirators are recommended for outdoor use when mixing and
applying pesticides. |
When carrying out operations, change
filters each day. The cartridge should be replaced when chemical odour becomes apparent or
when breathing becomes difficult. New cartridges should always be installed at the
beginning of spray season. Prior to commencing work, check the face seal while the
respirator is on the wearer's face. Regardless of design, respirators cannot be worn
securely by people wearing beards, moustaches or sideburns. |
Face Shields |
Goggles offer protection, but frequently
full-face protection is advised or required according to the pesticide label. It is
especially important to protect your eyes and face when pouring or mixing liquid
concentrates. Effective face shields are made of clear plastic. |
Since the shield attaches to the hard hat,
you can raise or lower it as needed. |
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Avoiding Spray Drift
To minimize the
risk of drift, follow these guidelines:
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Do not use air-blast or air-mist sprayers to apply herbicides.
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Do not spray in winds above 20 km/h (12 mph).
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Avoid using nozzle pressures above 45 psi (300 kPa).
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Use a minimum of 45 L/acre (10 gallons/acre) water for all herbicides unless otherwise
specified for the product.
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Do not spray when the wind is blowing towards a nearby sensitive crop, shelterbelt or
garden.
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Select nozzles that will produce uniform patterns, correct application rates and low
drift hazards. For most conditions, 80o flat fan nozzles produce a better
combination of pattern uniformity and drift control than do flooding nozzles, 65o
or 73o flat fan nozzles, or cone nozzles.
- Refer to the Manitoba Agriculture, Food and Rural Initiatives publication "Field Sprayers" and
the fact sheet "Calibration and Metric Conversions for Farm Sprayers" for
additional information on spraying equipment and calibration.
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Laundering Pesticide Soiled Clothing
Skin can absorb chemicals from clothing and equipment that have not been handled and
washed properly. Additionally, improper laundering can result in contamination of the
washing machine or dryer.
Just as the operator needs to be cautious when handling pesticides, the person doing
the laundry needs to be cautious when handling pesticide soiled clothing.
Consult the Manitoba Agriculture, Food and Rural Initiatives factsheet "Protective Clothing for Use
with Pesticides" for further information.
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Container Disposal
Rinse all containers prior to disposal to reduce environmental contamination caused by
open dumping of unwanted containers.
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Triple Rinsing
Triple rinsing renders used pesticide containers (metal, plastic, glass) more than 99.9
percent free of residues, in most cases. Recent data shows that over 78 percent of
pesticide containers are being rinsed by farmers. Here are the steps that should be
followed:
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Empty contents of the container into the spray tank and drain in a vertical position for
30 seconds.
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Add a measured amount of rinse water or other dilutent so container is about one-fifth
full.
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Rinse the container thoroughly and pour the rinsate into the spray tank.
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Repeat the procedure two times; it should only take about 5 minutes in total.
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Triple rinsed containers should be punctured or broken to render them non-reusable.
Paper bags should be rinsed once prior to disposal.
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Pressure Rinsing
Also available are pressure rinsers that can rinse all sizes of empty pesticide
containers that can be lifted into position over the spray tank. A 30-second rinse with a
pressure rinser is convenient and just as effective as triple rinsing. Pressure rinsers
are constructed to be thrust into the bottom of a metal can or plastic jug.
Holes, situated laterally in the rinser tip, direct water from a pressurized source
against the inner sides of the container and effectively wash the residual pesticide into
the spray tank.
Some farmers have found it convenient to attach a rinser to the pump on their large
water storage tank to minimize container handling. Pressure rinsers have the added
advantage of rendering containers useless by automatically puncturing them.
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Disposal of Containers
Properly rinsed containers should be delivered to a designated pesticide container
disposal site. Contact your Agricultural Representative or Weed Supervisor for the
locations of pesticide container disposal sites in your municipality.
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Pesticide Formulations and
Compatibilities
Abbreviations associated with product names indicate the type of formulation.
Abbreviations most often used are:
E or EC = emulsifiable concentrate
W or WP = wettable powder
SC = spray concentrate
WDG = wettable dispersable granules
DF = dry flowable
When tank mixes are being considered follow any specific label instructions and check
label for incompatibilities. Compatibility is usually better if WP is mixed with WP. EC
formulations are more likely to cause compatibility problems when mixed with WP
formulations.
Compatibility charts only indicate physical mixing properties and do not indicate
chemical interactions and for that reason are not included in this guide.
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For more information, consult Fruit Crop Protection Guide
for Commercial
Growers
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