Pesticide Use

Before using a pesticide, it is very important that you read the label in its entirety and understand all of the safety precautions that should be taken when handling it, mixing it, applying it, storing it, and disposing of it.  You should also note what type of first aid is required should you inhale it or your skin, eyes, or other parts of your body come into contact with it so that you can be prepared in case of an accident. 

Pesticide Label vs. Labeling

A pesticide label is the information that is printed on or attached to a pesticide container.  It contains a lot of information, but generally provides information about the product and how to properly use it.  Labeling includes not only the label on the contain, but also any other brochure, booklet, flyer, or additional labels that accompany the product.

The brand name or trade name is typically the most prominent name on the front of the label.  They are the name under which the product is marketed.

Labels typically indicate the formulation of the pesticide in the container.  Different formulations must be handled and prepared differently.  Pesticides are often available in different formulations.

Because pesticides often have complex chemical formulas, a common name or chemical name is often assigned to a pesticide to make it easier to identify.  If there is a common name, it is often listed in the active ingredient statement on the label.

The name and address of the manufacturer or distributor must always be printed on the label.  This is required by law.

The net quantity of product is printed on the label.  It can be expressed using a variety of measurement units like gallons, quarts, pints, pounds, ounces, grams, etc.

Pesticide labels are required to include a registration number from the Environmental Protection Agency (EPA).  This is used to indicate the pesticide has been registered with the EPA for the specific uses shown on the label, but it does not mean that the EPA “approved” the pesticide for use.

Labels contain an establishment number.   This indicates which factory or establishment produced the pesticide.

All pesticide labels must include an ingredient statement specifying the active ingredient(s) and the percentage of the active ingredient(s) by volume.  While manufacturers are required to include the active ingredient(s), they are not required to list the inert ingredient(s).

Signal words are required by the EPA to appear on most pesticide product labels to indicate the relative toxicity of the pesticide to humans.  Pesticides are tested for toxicity in laboratory animals to determine the dosages at which death will occur in an average human when swallowed, when applied to the skin, and when inhaled.  The They are also tested to determine the level of irritation or corrosiveness that occurs when certain dosages contact the eyes and skin.  Of the five-criterion tested, the one with the highest level of toxicity determines the overall toxicity of the product.

The signal word must appear in large letters on the label’s front panel with the text “Keep Out of Reach of Children.” The general definition of the signal words are as follows:

CAUTION:  The product is slightly toxic orally, dermally, or through inhalation; or it causes slight eye irritation.

WARNING:  The product is moderately toxic either orally, dermally, or through inhalation; or it causes moderate eye and skin irritation.  AVISO (Spanish for WARNING) must also appear on the label.

DANGER:  The product is highly toxic by at least one route of entry into the body.  These products can cause severe eye damage or skin irritation.  PELIGRO (Spanish for DANGER) must also appear on the label.

DANGER/POISON:  The product is highly toxic by all routes of entry into the body and cause death in very low doses.  PELIGRO (Spanish for DANGER) must also appear on the label.  The word POISON must be in red letters.  These words must always be accompanied by a skull and crossbones symbol. 

Labels will contain several types of precautionary statements.  These should indicate how the product may be poisonous to man or animals and any safety measures that should be taken to avoid being poisoned (such as any special protective gear that should be worn).  It should indicate an any potential environmental hazards and precautions taken to prevent them.  And finally, it should indicate all fire, explosion, or chemical hazards posed by the pesticide.

Labels should contain a statement of practical treatment (i.e. first aid).  This section of the label will describe first aid measures that should be taken if the pesticide is ingested or inhaled or if it comes into contact with the skin or eyes, as well as which types of exposure require medical attention.  In the case of a level of exposure requiring medical attention, the pesticide label should be taken to the doctor.

Directions for use will appear on the label of all pesticides providing a lot of important information.  They will indicate on which crops, animals, or other items the pesticide can be used, pests the product is registered to control, the formulation in which you should apply the product, the quantity of product to use, where and when to apply, the equipment needed to apply the product, and sometimes which equipment should not be used for application.  Always read the directions before buying to be sure you have all the necessary equipment for application and safety.

There are often misuse statements on the label.  Because it is against federal and state law to use pesticides in a way not consistent with its label, manufacturers will often include warnings against misuse on the label.

Most pesticide labels will also include information on storing and disposing of the product correctly.  Disposal instructions are typically general since this varies by location.  Regardless of whether the label states it or not, pesticides should always be stored in a secure, locked location so that children cannot get to them.

Mixing Pesticides

When mixing pesticides, be sure to follow the direction on the label.  Formulations for home use will typically indicate the pesticide formulation to water ratio.  Usually the amount of pesticide required will be measured in teaspoons, tablespoons, or ounces per gallon of water.  Wear all personal protective gear like gloves, goggles, etc. that are recommended on the product label.

It is recommended that you do not use the same application equipment (hand sprayers, hand dusters, hose end sprayers, compressed air sprayers, etc.) to apply mixed pesticides as you use to apply herbicides.  No matter how well you clean them after each use, there will always be residue left in the container.  It is better to maintain one set of application equipment for pesticides and another set for herbicides.

Calibrating Pesticide Application Equipment

If a pesticide’s instructions indicate  a specific number of teaspoons, tablespoons, or ounces of pesticide to mix with a gallon of water for a given area,  this is likely enough for a homeowner to do a decent job estimating the rate at which the product should be applied.  But not all pesticides (especially herbicides and insecticides) give rates in teaspoons, tablespoons, or ounces per gallon.  Instead they give them in teaspoons, tablespoons, or ounces for a given area like 100 square feet.  In cases such as this, it is dangerous for the homeowner to guess at the concentration to be mixed as they could over-apply, possibly killing plants and causing unnecessary expense, or under-apply, causing the pesticide to be ineffective at controlling the pest.  Applying chemicals at the wrong rate is dangerous to humans and the environment.

To avoid this, spraying equipment should be calibrated, which is relatively simple.  Once calibrated, record the settings for future reference.  Because wear and tear on equipment might change rate of application over time, it is best to recalibrate at the beginning of each season.  Calibration of a home sprayer can be done as follows:

  • Fill the sprayer container with water only. Fully pressurize the sprayer and spray water into a pint or quart jar, recording the time it takes to deliver some fixed amount of liquid through the sprayer into the jar.  For example, spray into the jar for 30 seconds and measure how much was sprayed.
  • Determine the size of the area that is to be treated. This is usually easy to estimate by dividing the area into triangles and rectangles and summing the areas of each individual triangular and rectangular areas.  The area of a rectangle is simply length times width.  The area of a triangle is one half of the base times height.
  • Next, you must determine how big an area you can cover in some fixed time. Spray an area with water a normal working speed for some fixed time like 30 seconds.  Measure the area sprayed to determine how many square feet were sprayed during that fixed time of 30 seconds.

Assuming the time used in step 1 to measure how much the nozzle can deliver and the time used in step 3 to determine what area can be covered were both the same time period (30 seconds in the above example), then the formula to calculate how much to pesticide to mix up would be as follows:

Amt to Mix = step 1 amount  x  (step 3 area  /  step 2 area)

Or

Amt to Mix = 6 oz  x  (750 sq ft  /  75 sq ft)  =  6 oz  x  10  =  60 oz

If the label calls for 4 tbsp (2 oz) of pesticide per 1000 sq ft of coverage and you only need to cover 750 sq ft, then you need to mix 1.5 oz of pesticide (2 oz  x  750/1000 or 2 oz  x  0.75) with 58.5 oz of water to get the 60 oz of solution needed to cover the 750 sq foot area.

If using a compressed air hand sprayer typical of most household use, remember to pump the container often to maintain a relatively constant pressure.  Be sure to spray the area evenly with as little overlap as possible.  Ideally, you should spray in an arc no more than 3- to 4-feet on each side of the applicator.  There is no need to stop to spot treat pests located along the way as the application rate calculated above should already be enough to kill any pests in the area.

Some other application equipment like hose end sprayers (containers containing premixed pesticide which are screwed onto the end of a water hose for dispersal) provide for less uniform coverage.  When hose end sprayers are used, they disperse the maximum amount in the beginning and gradually disperse less until the container is empty.  In such cases, it is often better to cut the application rate in half and cover the area twice, once moving back and forth on a north-south line and a second back and forth on an east-west line.

Pesticide Application

Those applying pesticides should wear at a minimum all recommended personal protective equipment specified on the product label.  You can always wear more protective gear to be extra safe, but never less. 

Always check that the application equipment is working properly before each use.  Fill with water and test the sprayer.  Look for clogs and leaks in the nozzle and hoses by spraying water.  Once you are sure that everything is working properly, mix the pesticide for application.

Before applying make sure that there are no people, pets, or livestock near the area that is to be treated.  Apply pesticides when there is no wind to avoid the pesticide drifting onto untargeted areas.  Winds are typically minimal in the early morning or late evenings.

Cleaning Pesticide Application Equipment

After each use, you should thorough clean your application equipment.  If you have mixed pesticide solution left over, then dispose of it according to the product label.  This might mean spraying it onto areas that the label states are safe areas.  Thoroughly clean the equipment with water, remembering to flush the hose and nozzle.  Disperse the rinse water over a large area instead of dumping it all in a concentrated area where it might do unwanted damage to plants or crops.  Never dump the rinse water from pesticide application equipment down the drain.

Storage and Disposal of Pesticide

Always store pesticides in their original contain in a locked cabinet to prevent children from getting to them.  They should be stored in a location that does not experience extreme cold or heat since freezing and overheating can damage or alter the chemical makeup of the pesticide.  Never store pesticides inside your home. 

Dispose of pesticide containers by following the instructions located on the label.  Some states have disposal sites specifically for pesticides while others do not.

Symptoms of Pesticide Poisoning

Pesticide poisoning is often hard to detect without laboratory tests. Symptoms are often very similar to common illnesses like food poisoning or the flu. In some cases, the person poisoned may appear to be drunk, with symptoms like slurred speech, poor coordination, confusion, and sleepiness.  However, poisoning by most common pesticides affects the nervous system and presents with symptoms that develop in stages that get progressively worse depending on the level of exposure.

The earliest stage of acute poisoning or only stage for mild poisoning often presents with symptoms like fatigue, dizziness, blurred vision, headaches, nausea, vomiting, excessive sweating, excessive salivating, stomach cramps, and diarrhea.  As moderate or acute poisoning progresses, the previous symptoms may become more severe as other symptoms develop like weakness, constriction of the pupils, inability to walk, discomfort in the chest, and muscle twitching.  In the case of severe or acute poisoning, the previously mentioned symptoms may get worse and lead to convulsions, secretions from the mouth, unconsciousness, and even death. 

First Aid for Pesticide Poisoning

Before using a pesticide, you should always read the label’s “Statement of Practical Treatment” section to understand how to treat yourself should you be poisoned by it.

If a pesticide gets on your skin, you should remove all contaminated clothing and wash the areas of the skin that contaminated with the pesticide immediately.  But do not scrub your skin with a brush.  Wash your hair if exposed and clean under your fingernails. Use detergent to wash as it works better than soap at removing pesticides.  Your clothes should be washed thoroughly washed with detergent.

If someone inhales pesticide, they should immediately seek fresh air and remove any tight clothing. If they stop breathing, administer artificial respiration until they begin breathing again or medical assistance arrives. 

In case of poisoning, seek medical help immediately.  Be ready to give the name, age, and sex of the victim, as well as to identify yourself and your relationship to the victim.  Be sure to have the poison product on hand so that you have all the necessary information from the label needed by physicians to come up with an appropriate treatment plan.

Environmental Considerations for Pesticide Use

Before using pesticides, think.  Question whether there are other less risky controls that can be implemented that will produce similar results with less risk to the environment.  There are many ways that pesticide use can go bad, from drift to run off to improper application and more.  If all other non-chemical control measures have failed and you must use pesticides, select the one that will control the targeted pest with minimal risk to the environment.

When using pesticides (especially insecticides), attention should be placed on protecting pollinators such as honeybees.  Those that are highly toxic to bees will often have special instructions about when and how to apply to minimize the risk to bees.  Avoid applying insecticides when the temperatures are low as it will call residue to remain longer.  Bees are typically less in the very early morning and late evening.

Most pesticides break down quickly.  Some, however, break down very slowly and remain in the environment for a long time.  Repeated applications of pesticides will cause more and more of the product(s) to accumulate in the soil.

Home Garden Pesticides vs. Commercial Pesticides

Home-garden pesticides are packaged in small quantities like pints, quarts, ounces, or pounds.  They are typically only mildly or moderately toxic.  It is rare that pesticides packaged for home-garden are highly toxic.  They are usually available only in low concentrations.

Commercial pesticides while typically less expensive are much more toxic and formulated in higher concentrations.  This makes handling them more dangerous.  When applying them, commercial pesticides require special protective clothing and equipment.  They come in much larger quantities than a homeowner would ever use.