Mix It Right, Apply It Safely: Pesticide Best Practices

Pesticides are powerful tools on the farm, but they are not without risk. Understanding the essentials of pesticide safety can help prevent unintended exposure for people and the environment. February is National Pesticide Safety Education Month, and this is a great time to review pesticide safety practices on the farm. 

“Today, pesticides are used in and around homes, apartments, workplaces, farms, and a myriad of other settings to control weeds, insects, disease-causing organisms, rodents, and other pests,” said Fred Whitford, PhD, director of Purdue Pesticide Programs at Purdue University. “That means everyone benefits when we focus on pesticide safety education.”

Below are some top considerations to stay safe when working with and around pesticides.

Pesticide Applicator License 

For farmers adding restricted use pesticides (RUPs) to their management plans, obtaining a pesticide applicator certification is an important first step. Without one, farmers cannot buy RUPs from their co-ops or other local dealers.  

Each state has its own certification program. In Iowa, there are two main types of pesticide applicator certifications:

• A private applicator certification is for anyone using a RUP on land they own or lease. For most farmers, a private applicator certification should be sufficient on their own farms.
• Commercial applicator licenses are divided into several subcategories. Certifications are required for anyone looking to be paid for pesticide application services. 

A commercial applicator must be certified for each category of pesticide they apply.

In Iowa, the Department of Agriculture and Land Stewardship (IDALS) oversees all pesticide applicator certifications. Each person looking to obtain a certification must pass an exam covering the basics of pesticide use. 

“There are also special certifications,” said Betsy Danielson, an Extension specialist for Iowa State University Extension and Outreach in the Pesticide Safety Education Program. 

“For example, if you’re going to fumigate a grain bin, then you also need to take some additional exams. It’s really important to work with the Department of Agriculture to find out exactly what you need.” 

Editor’s Note: While the EPA identifies RUPs, the process to obtain a certification varies from state to state. This example focuses on pesticide applicator certifications in Iowa. While the process may be similar in your area, please ensure you work with your state agency to stay compliant.

Personal Protective Equipment (PPE)

When mixing and applying pesticides, you’re never fully dressed without the proper PPE. Selecting PPE starts with scanning the product label and looking for signal words to indicate the chemical’s toxicity. 

“The label is the law, and there is typically a section that discusses the required PPE for that product,” said Michelle Wiesbrook, University of Illinois Extension specialist in pesticide safety education. The standard baseline PPE includes pants, socks, shoes, and a long-sleeve shirt, Wiesbrook explained. Depending on the product, it can also include an apron, safety glasses, a face shield, and a respirator. Many also require chemical-resistant gloves. “I recommend gloves with any product,” Wiesbrook said. 

Always wash your PPE separately from the family laundry because pesticide residues can transfer to other items in a mixed load. “If you spill anything concentrated on your clothes, or it is a pesticide that is highly toxic, we recommend you just throw those clothes away,” Wiesbrook said.

Mix It Up

There are multiple components that go into spray tanks and through sprayer lines and booms, and they must be added in the right mixing sequence.

“Mixing order is critical in preventing compatibility problems,” said Jim Reiss, former vice president of product development and technical services at Precision Laboratories. “Many times, it’s not super-complicated tank mixes that cause problems. It’s some of the simple ones.”

Most crop protection product labels state a preferred mixing sequence. If you’re still not sure, simply conduct a small compatibility test to verify the mixing order that produces the most stable tank mix. Crop protection labels contain directions for conducting compatibility tests. 

According to a publication by Oklahoma State University, the proper mixing sequence is as follows:

1. To begin, fill a clean tank 50%–75% full with clean water or another carrier. If an inductor is used, rinse it thoroughly after adding each component. Add compatibility agent and/or defoamer at this time.
2. Add dry products such as ammonium sulfate (AMS). 
3. Add water-dispersible products, microcapsule suspensions. 
4. Next, add soluble liquids, emulsifiable concentrates.
5. Add surfactants last. 

Transporting Pesticides Safely

When transporting pesticides, extra precautions are necessary to avoid potential problems in the event of an accident or spill. 

“Most of the risk that we have is not from storage or fires; it’s transportation,” Whitford said. “On a scale of 1–10 risk-wise, transportation is 10; almost everything else would be 2 or 3.” 

It’s important to be aware of federal and state departments of transportation (DOT) pesticide requirements. “There’s federal regulations, and under DOT, farmers are given many kinds of exceptions,” Whitford explained. “Individual states may require additional regulations above and beyond the federal DOT standards.” 

Secure the load. Losing cargo on the road can be serious, particularly with pesticides. Not only is it a loss of product — whatever falls is likely spilled or damaged — but it can also cause injury to people and the environment. 

If insurance doesn’t cover the cost of remediation, you have to pay for cleanup and restoration. “One mini-bulk on the side of the road cost a farmer $55,000 to have the contaminated soil transported from Indiana to Alabama to a special remediation site,” Whitford said. The costs can be much steeper if hospital bills and litigation are added. Some $15 tie-downs and a few minutes of time can save thousands. 

Transport pesticides in original, labeled containers. “When hauling, be sure to have materials in proper containers with the proper names,” Whitford explained. “In the event of an accident and spill, the emergency responder will know what the products are, so they can react appropriately.”

Control, contain, clean up. Make sure you are traveling with a spill kit, including chemical-resistant gloves, absorbent material such as kitty litter, coveralls, a shovel, and a temporary plastic storage container.

Also, store protective equipment, such as gloves and a change of clothing (easy solution: a Tyvek suit), within the vehicle, away from the pesticide. A significant spill, such as during an accident, would require contacting poison control and emergency management. The main goal, Whitford said, is to keep the products from getting into water directly or through drains.

Always treat any pesticide with the utmost care. Used correctly, they can protect crops from unwanted pests and maintain farm profitability. Used incorrectly, they can become an environmental hazard.

Assistant Agronomy Editor Chelsea Dinterman and Gil Gullickson also contributed to this article.