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Horticulture & Home Pest News is filled with articles on current horticulture, plant care, pest management, and common household pests written by Iowa State University Extension specialists in the Departments of Entomology, Horticulture and Plant Pathology.

Understanding Pesticide Labels

This article was published originally on 1/12/1994
Every pesticide purchased today, regardless of whether it controls insects, weeds, or diseases has a label with instructions on how to safely use the product. Some labels are easy to understand, others leave you feeling like you're alone cutting through political red tape.

The label means different things depending upon your point of view. The label is a "license to sell" to the manufacturer. To the state or federal government, the label is a way to control the distribution, storage, sale, use, and disposal of the product. To the buyer or user, the label is a source of facts on how to use the product correctly and legally. To physicians, the label is a source of information on proper treatment for poisoning cases. All labels must contain certain information. Each item will be addressed individually.

First is the brand, trade, or product name. Every manufacturer has a brand name for its product. Different manufacturers use different brand names for products containing the same active ingredient. Most companies will register brand names as a trademark which restrict other companies from using that name. The brand or trade name is the one used in ads and by company salespeople, it also shows up plainly on the front panel of the label. An example of how a brand name can become associated with a product can be seen with facial tissue. Many of us commonly refer to facial tissues as Kleenex's. Kleenex is the brand name. Jell-O is another such example. In the world of herbicides, Kleenup (an Ortho product) and Roundup (a Monsanto product) have the same active ingredient and thus perform the same job. It is critical not to be caught purchasing and using a product by brand name alone. Some companies use the same basic name with only slight variations to designate entirely different pesticide chemicals.

It is much more reliable to purchase a product based on its common name. A common name is a shortened, simpler version of the complex chemical name. These are included in the ingredient statement on the label. Only common names which are officially accepted by the U. S. Environmental Protection Agency may be used in the ingredient statement of the pesticide label. The chemical name is the complex name which identifies the chemical components and structure of the pesticide. For many of us without a chemistry background, all they represent is a challenge in pronunciation. The chemical name is also listed in the ingredient statement. The other requirements of the ingredient statement is to include the amount (in percentage) of each ingredient listed. Inert ingredients need not be named, however, the percentage of the total contents they comprise must be shown.

On the front panel of the pesticide label is a statement indicating the type of pesticide and general terms of what the product will control. It is important to remember that the term pesticide is a broad umbrella under which insecticides, fungicides, herbicides, and algicides fall. Insecticides control insects, fungicides control diseases, herbicides control tree, brush, and weed growth, algicides control the growth of algae. A pesticide is limited in what it will successfully control. Thus carbaryl, an insecticide will control certain insects, but will not control plant diseases or weeds. The front label also includes the net contents. This can be expressed in pounds, or ounces for dry formulations, and as gallons, quarts, or pints for liquids. Liquid formulations may also list the pounds of active ingredient per gallon of product.

Law requires the maker or distributor of a product to put the name and address of the company on the label. This is so you will know who made or sold the product. Registration and establishment numbers are used in case of accidental poisoning, claims of misuse, or liability claims. An EPA registration number appears on most pesticide labels. This is an indication that the pesticide label has been approved by the federal government. In some situations, a pesticide may be used where a special local need (SLN) arises. This product's usage would only be allowed where that product is registered. An establishment number identifies the facility that produced the product. In instances where problems occur, the facility that made the product can be traced.

Signal words and symbols used on the label are important clues in recognizing how potentially dangerous the product is to humans. The signal word must appear in large letters on the front panel of the pesticide immediately following "Keep Out of Reach of Children" which must appear on every pesticide label.

DANGER signals that the pesticide is highly toxic. A taste to a teaspoonful taken by mouth could kill an average sized adult. Any product which is highly toxic orally, dermally, or through inhalation or causes severe eye and skin burning will be labeled "DANGER." In addition, all pesticides which are highly toxic orally, dermally, or through inhalation will also carry the word "POISON" printed in red and the skull and crossbones symbol.

WARNING signals that the product is moderately toxic. As little as a teaspoonful to a tablespoonful by mouth could kill the average sized adult. Any product which is moderately toxic orally, dermally, or through inhalation or causes moderate eye and skin irritation will be labeled "WARNING."

CAUTION signals that the product is slightly toxic. An ounce to more than a pint taken by mouth could kill the average adult. Any product which is slightly toxic orally, dermally, or through inhalation or causes slight eye and skin irritation will be labeled "CAUTION."

Other precautionary statements are included on pesticide labels to help you decide the proper steps to take to protect yourself, your helpers, and other persons (or domestic animals) which may be exposed. These statements are sometimes listed under the heading "Hazards to Humans and Domestic Animals." They are composed of several sections and many are self explanatory.

Statements which immediately follow the signal word, either on the front or side of the pesticide label, indicate which route or routes of entry (mouth, skin, lungs) you must particularly protect. Many pesticide products are hazardous by more than one route. Typical DANGER label statements include:

Fatal if swallowed,
Poisonous if inhaled,
Extremely hazardous by skin contact--rapidly absorbed through skin,
Corrosive--causes eye damage and severe skin burns.

The statements are not uniform on all labels, and many variations may be found. A single label can have several precautions stated.

Typical WARNING label statements include:

Harmful or fatal if swallowed,
Harmful or fatal if absorbed through the skin,
Harmful or fatal if inhaled,
Causes skin and eye irritation.

Typical CAUTION label statements include:

Harmful if swallowed,
May be harmful if absorbed through the skin,
May be harmful if inhaled,
May irritate eyes, nose, throat, and skin.

CAUTION statements are usually more moderate and warnings are qualified with "may" or "may be" thus keeping with the lower toxicity levels of products possessing a CAUTION label.

Following the Route of Entry statements are the Specific Action statements. They tell the consumer the specific action that should be taken to prevent poisoning accidents. The statements are related to the toxicity of the pesticide product (signal word) and the route or routes of entry which must be particularly protected. Do not breathe vapors or spray mist, avoid contact with skin or clothing are common specific action statements which help prevent pesticide poisoning.

Protective Clothing and Equipment statements are listed on many pesticides and should be followed closely. In spite of the fact that some labels do not contain these statements, this doesn't mean that protection isn't necessary. Long-sleeved shirts, long-legged trousers, and gloves should be worn when applying all pesticides.

The Statement of Practical Treatment gives the recommended first aid treatment in case of accidental poisoning. All DANGER and some WARNING and CAUTION labels contain a note to physicians describing the appropriate medical procedures for poisoning emergencies and may identify an antidote.

The Environmental Hazards statement warns of potential hazards to the environment. Read closely for special warning statements. Special Toxicity statements warn of potential hazards to wildlife, insects, or aquatic organisms. These statements help us choose the safest product for a particular job. General Environmental statements appear on almost every pesticide label. They are reminders to use common sense to avoid contaminating the environment. Physical or Chemical Hazards statements tell of special fire, explosion, or chemical hazards the product may pose. The Classification statement indicates whether the EPA has classified the pesticide as a "general" or "restricted" use pesticide. Just because a product is a "general" use pesticide, doesn't mean that the product has a low hazard level. Use the signal words and precautionary statements to judge the toxicity hazard of the pesticide.

Some pesticide labels with the signal word "DANGER" or "WARNING" contain a Reentry statement. This statement tells how much time must pass before people can reenter a treated area without appropriate protective clothing. These reentry intervals are set by both EPA and some states. In many cases reentry intervals set by states are not listed on the label. It is the responsibility of the consumer to determine if one has been set. The reentry statement may be printed in a box under the heading "Reentry" or it may be in a separate section with a title such as "Important," "Note," or "General Information." If no reentry statement appears on the label, then sprays must be dry or dusts must be settled before reentering or allowing others to reenter a treated area without protective clothing. That is the minimum legal reentry interval. The Ortho Weed-B-Gone Weed Killer label contains no reentry statement; however, minimum reentry tells us we must wait until the spray dries before reentering the treated area ourselves or allowing others including pets in the treated area. All pesticide labels contain general instructions for the appropriate Storage and Disposal of the pesticide and its container. State and local laws vary considerably so specific instructions are usually not included.

Directions for Use is probably the most important part of the label. This is the part of the label that tells you, the consumer, how to use the product. It gives information about the pests the product claims to control; the crop, animal, or site the product is intended to protect; the form in which the product should be applied; the proper equipment to be used; how much to use; mixing directions; compatibility with other often-used products; phytotoxicity; other possible injury or staining problems; as well as where and when the material should be applied. Additional information includes the least number of days which must pass between the last pesticide application and harvest of crops. This is known as the pre-harvest interval (PHI). This interval is set by EPA to allow time for the pesticide to break down in the environment which prevents illegal residues on food, feed, or animal products and possible poisoning of grazing animals.

The important message I'm trying to get across is READ THE LABEL. Read it before you purchase the pesticide, before you mix the pesticide, before you apply the pesticide, and before you store or dispose of the pesticide. Another important message is Understand What You Are Reading and ask questions if you don't. The only dumb question is the one which is not asked! Also included on all pesticide labels is the notice that states the buyer assumes all responsibility for safety and use not in accordance with directions. So, if a salesperson sells you a non- selective herbicide product to control a few broadleaf weeds in your yard and you apply the product to the entire lawn without reading the label, don't be angry with the salesperson when your entire yard is dead. It's you who didn't read and understand the label!!! The information in this article was taken from the guide, Applying Pesticides Correctly, A Guide for Private and Commercial Applicators.

Year of Publication: 
IC-467(1) -- January 12, 1994