Grower 101: Using Pesticides Correctly By David Barcel and Marla Faver

Pesticides are important tools in greenhouse production. Without them, it would be very difficult to produce the plant quality expected by consumers. While a greenhouse facility provides numerous benefits for producing high-quality, desirable ornamental plants, it's also an excellent place for pests. For this reason, the judicious and safe use of pesticides as part of an integrated pest management (IPM) program is an important production tool for growers.

The term pesticide is used often, but do we really understand what a pesticide is or what is included in the term pesticide? Pesticides are synthetic or natural chemicals that eliminate, prevent or control pests. What is considered a pest? A pest is a living organism that attacks us or competes with us for food, fiber or desirable plants and products.

Pests fall into five main groups: insects, including mites, ticks, spiders and nematodes; snails and slugs; vertebrates, such as rats and moles; plant disease agents, such as fungi, bacteria and viruses; and weeds, which are defined as plants out of place. The first step in successful pest control is accurate identification of the problem. The second step is identifying the appropr-iate method of control and then carrying out this method in the safest manner possible. If chemical control is appropriate, then the label for that chemical must be read and clearly understood before using the product.

Follow The Label

Successful pest control is the final goal for growers and applicators, but the most important aspect of pest control is safety. It is the applicator's responsibility to carefully read and follow all directions on the product label. The label is the primary information source for the chosen pest control product. It describes the product's uses as well as its risks and benefits.

The product label includes the trade name used by the manufacturer, the common name accepted by the Environmental Protection Agency (EPA) to identify the active ingredient and the chemical name for the active ingredient. Manufacturers use trade names to sell products and distinguish them from other products containing the same active ingredient. When reading the label, you will find the active ingredient expressed as percent by weight or pounds per gallon contained in the package.

The trade name will oftentimes distinguish the type of formulation for the product. Products are available in different dry forms:

  • Wettable powders (WP) are powders applied as suspensions after dispersion in water.
  • Water dispersible granules (WG) are free-flowing granules that disperse or disintegrate in water to form a suspension or solution.
  • Granules (GR) are free-flowing solids of defined size range that are ready to use.

Products are also available in other forms:

  • Suspension concentrate (SC) is a stable suspension of active ingredient in water intended for dilution with water before use.
  • Emulsifiable concentrate (EC) is a liquid, homogeneous form to be applied as an emulsion after dilution with water.
  • Fumigants (FU) or aerosols (AE) release the active ingredients in the form of a smoke or very fine particle.

Also On The LabelÉ

The name and address of the manufacturer is included on the label as well as the EPA registration number and EPA establish- ment numbers. The registration number verifies that the product has been registered with the U.S. EPA. The establishment number tells what facility made the product.

Each product label also contains a signal word designated by the EPA to give users an idea of the overall toxicity of the product. Pesticides are grouped into three categories based on relative toxicity. The signal words are danger (highly toxic), warning (moderately toxic) and caution (low toxicity). The skull and crossbones symbol and the word "poison" printed in red are required on all labels with the signal word danger. They may require a special permit for use.

Other precautionary statements found on the label specify hazards to humans and domestic animals along with first aid statements in the event of inadvertent exposure. Environmental hazards advise of the toxicity to wildlife and endangered species as well as water and soil.

When the EPA registers a pesticide, it determines whether the product may be sold for general or restricted use. It will be clearly stated on the label if the product is for restricted use only. Restricted-use pesticides are of greater toxicological or environmental concern than general-use pesticides and, therefore, are more restrictive as to who can handle them.

Safe Usage

For all products labeled for use in agricultural crop production, the label contains a section called the Agricultural Use Require-ments. This section contains information about use of the Worker Protection Standard and its requirements for the protection of workers, such as training, decontamination, notification and emergency assistance. Of significant importance is the specification of the re-entry interval (REI) in the Agriculture Use Requirement box.

Product-specific REIs can range from zero hours to upwards of seven days and determine the amount of time that must pass between pesticide application and the time it is permissible for a person to come in contact with the treated areas without the need for personal protective clothing.

Directions for use will tell you where the product can be applied, what crops/plants the product can be used on, the pests it is registered to control, the use rates and the timing of applications. In the case of food crops, the label will also state how long to wait from the time of application to harvest. The label may reference other documents for additional use directions, and it is the user's responsibility to read and follow all referenced directions as well as the directions stated on the label. Additional directions and requirements can be found with pesticide dealers, company representatives, land-grant universities, extension agents, or commodity or industry organizations.

You should read the label before purchasing the product to determine if it is the correct product for the problem and if you can meet the stated requirements for safety and disposal, such as providing the required personal protective equipment for the mixer and applicator. The label should be read again just prior to use to ensure proper mixing, application, storage and disposal.

Pesticide Training And Safety

Many states require yearly worker safety training to ensure the proper use of pesticides. Employees should fully understand the product label information presented in this article, including product name, formulation and active ingredient, signal word, precautionary statements, REI, pests controlled and labeled dosage rates. Additionally, they should know information regarding crop safety, application methods and application intervals. Equally important is having and understanding the Material Safety Data Sheet (MSDS), as this document provides important information regarding hazards, first aid measures, firefighting measures, accidental release measures, transportation and other regulatory information.

Safety training includes availability and use of required personal protective equipment (PPE), such as gloves, coveralls or spray suits, safety glasses or goggles, and respirators. For optimum protection, all PPE must fit properly and be regularly inspected for rips, tears and, in the case of respirators, air leaks. A strong odorant such as banana oil can be used to check the fit of respirators. A doctor's evaluation stating the respirator will not be an added stress to the heart or lungs may be required for some individuals. Other safety equipment should include spill containment kits, eyewash stand or bottles, and a first aid kit.

Mixing And Application Equipment

The user must know how to mix, load and apply products according to the label. Always read the label directions each time a pesticide is used. When handling pesticides, keep the pesticide container below eye level to help prevent a spill on the handler. Always mix and load pesticides in a bright, ventilated area. To accurately measure pesticides for mixing, a variety of measuring equipment may be required. For dry materials, scales that weigh in increments of ounces up to pounds will be needed. A small bucket is useful for premixing dry products into slurries before adding to the spray tank. For liquid products, calibrated measuring cups of various sizes are needed. And for products that use extremely low use rates, such as triazole plant growth regulators, you should have measuring pipettes on hand as well.

Application equipment should be checked for leaks, plugged strainers, corroded fittings and worn hoses. Never leave the equipment unattended when filling. Application equipment should be calibrated on a regular basis to ensure the pesticide is used as directed.

Referred to as a "bucket check," the user can calibrate spray volume for speed and area. One technique is to apply plain water over a given area, such as 100 sq.ft. First determine the time it takes the applicator to walk the given area, and then collect/measure the spray water applied into a bucket for that same amount of time. By doing this simple check, you will ensure that the proper spray volume is applied, good coverage is obtained and optimum pest control is achieved.

Remember to mix only the amount of product that can be applied at the time, as having excess or shortfall only creates waste or wasted time. Be sure to clean all mixing and application equipment as well as safety equipment after each use. Empty liquid pesticide containers need to be triple rinsed before disposal, and all empty containers need to be disposed of properly.

Storing Pesticides

Pesticide products should not be left out in the open during or after mixing and applications. The package should be immediately resealed and placed in a storage container during the application. Locked chemical storage units or rooms are a must and are required by many states. Many growers have utilized ship containers for this purpose. They are strong and waterproof and have a good amount of storage area. Ventilation should be included in all storage areas to prevent a buildup of odors, maintain reasonable temperatures and provide for proper air exchange. Most products remain viable and usable for many years if kept reasonably cool and dry.

For proper understanding and use of pesticide products, be sure to make time for reading and understanding the product label and MSDS. The proper training of all employees on mixing, loading and application of products will help ensure their safe and responsible use in your operation.

David Barcel and Marla Faver

David Barcel and Marla Faver are technical sales support representatives with Chemtura Corporation, Middlebury, Conn. For more information on this article, contact Tim Hodson at

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