When to reach for pesticides... not here!

What to Know Before Reaching for Pesticides

Lee ArmilleiField Notes

Pesticides are natural or synthetic products that are designed to kill, prevent, repel, or mitigate pests. A pest may be a weed, insect, animal, fungus, or another type of living organism.

Sub-categories of pesticides include herbicide, insecticide, rodenticide, fungicide, and more. When you see the suffix “cide” it typically means “act of killing”.

Pesticides come in various forms, including liquids, powders, granules, traps (sticky, pheromone, or otherwise), biological, and other forms.

Remember, products we consider “organic” or “natural” alternatives to synthetic chemical pesticides are still pesticides due to their application. So when you apply horticultural grade vinegar to weeds, it is a pesticide due to its application. Just because the product is natural, does not always mean it is better or safer. Applying horticultural vinegar will kill a weed, but it may also kill living organisms in the soil due to its strong acidity.

What are pests?

The EPA defines pests as “living organisms that occur where they are not wanted or that cause damage to crops or humans or other animals”.

More generally speaking, some plants (weeds), fungi, insects, bacteria, or animals may have a damaging affect to our cultivated landscapes or to the natural areas for which we care.

Some people view almost all insects as pests, particularly if they aren’t as pretty as butterflies and bees. However, keep in mind that some insects are beneficial. The larval stages of ladybugs look nothing like the adults we’ve come to recognize. In fact, they’re kind of scary looking. But ladybug larvae are very effective at controlling aphids, so the last thing you want to do is kill them.

Lady bug larva are effective in controlling aphids

Why use pesticides?

There are many reasons people reach for pesticides, some include:

  • The pest has lost its natural predator or check
  • The environment has become favorable to the pest
  • The area is too large to control with other measures
  • Other methods of control are more expensive
  • People misidentify pests

What is IPM?

Integrated Pest Management is an environmentally sensitive approach to managing pests. Practitioners use knowledge about the pest’s life cycle to use the least toxic means to manage or control it.

The US Environmental Protection Agency defines four steps to IPM:

Set Action Thresholds

Before you take any pest control action, first set an action threshold. Decide the level of tolerance for different areas of your property. For instance, you may treat your vegetable garden much differently than your turf grass. Seeing a pest does not mean you need to control it, so decide in advance what you find acceptable.

Identify and Monitor Pests

First identify potential pests. For instance, not all insects are pests. Many may be innocuous, and some are even beneficial. If you determine you have a pest, learn about its life cycle. Some controls are very effective at one point in a pest’s life cycle, and useless during others.

Then monitor populations. Sometimes, nature takes care of problems before they reach your action threshold. Remember, insects are part of a food chain. Leave them alone, and something might eat them before you need to do anything! This monitoring and identification ensures that you use appropriate pesticides and then only when they are really needed.


As a first line of pest control, IPM programs manage the landscape, to prevent pests from becoming a threat. Select healthy, disease resistant plants, and plant them where they will thrive. Avoid overly simple landscapes. These methods can be very effective and cost-efficient and present little to no risk to people or the environment.


Next, evaluate the proper control method both for effectiveness and risk. Always choose effective, less risky pest controls first. This starts with non-chemical options such as mechanical controls like weeding. Then select highly targeted chemicals, such as pheromones to disrupt pest mating. Finally, you may choose additional pest control methods, such as targeted spraying of pesticides.

Tips for using pesticides

  • Select the least toxic pesticide appropriate; consider natural or biological controls before synthetic controls.
  • Use the most selective or targeted pesticide available.
  • Read and follow all label directions.
  • Wear appropriate clothing (at minimum long pants, closed toe shoes, gloves).
  • Avoid using pesticides near water.
  • Apply pesticides only when weather conditions are favorable. This means as the label directs. Examples are low wind, dry, appropriate temperature, when overcast, or before precipitation.
  • Apply at the lowest functional rate. Do not assume that more product is more effective. Once you kill it, a pest can’t be more dead by using more chemicals.
  • Wash exposed skin and clothing when finished making applications
  • Store remaining pesticide in the original container with original label and at the appropriate temperature. If you move a pesticide to a new container, mark it accordingly, including the signal word on the label.
  • Clean all containers using the triple-rinse method. Use residual water on appropriate pests.

Consider other impacts of pesticides

Besides the target pest, pesticides impact humans, pets, water quality, soil quality, air quality, and non-target organisms. This impact varies among pesticides and concentrations applied.

Always check pesticide labels for toxicity levels. The signal words Caution, Warning, and Danger and Poison indicate increasingly toxic substances. Pesticides without a signal word are considered very low toxicity.

Additionally, pesticides vary in persistence, or the time they are active in the environment. Choose pesticides with low persistence to minimize their impact.

And finally, be aware that anyone who applies pesticides for a fee must be a certified pesticide applicator in the state they are working. Certified pesticide applicators must take extensive tests and earn continuing education credits to retain their license. This protects the applicator, the client, and the environment. Ask to see proof of such licensure from anyone applying pesticides on your property.

So you now see that best practices for using pesticides in the landscape requires thoughtful consideration. So the next time you notice a weed or insect in your landscape that doesn’t seem right, do a little research. Then follow the steps to IPM before reaching for a pesticide.