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What are Pesticides? Everything You Need to Know

Learn how to select and use pesticides safely in your home, yard, or garden

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what are pesticides

Pesticides are a cornerstone of the pest control industry and are broadly available for professionals and homeowners alike.

Even though pesticides are effective, widely-used compounds, they’re often misunderstood.

Unfortunately, not knowing how pesticides work or what they contain can be extremely dangerous.

In this blog, we break down everything you need to know about pesticides: from selection to safety.

What are Pesticides?

what are pesticides

Pesticides are substances used to control pest populations. These include insecticides (insect killers), rodenticides (rodent killers), and more.

While most pesticides are formulated from chemicals, others (called biopesticides) are made from viruses or bacteria strains targeted to control certain insects.

Although many people believe pesticides are solely to kill pests, that’s a misconception.

In fact, pesticides may attract, repel, interrupt the growth of, or sterilize a pest, depending on the formulation.

Ultimately, the goal of pesticides is to manage the populations of specific organisms and to complement other pest control efforts.

History of Pesticides

The history of pesticides is almost as long and storied as the history of humanity and agriculture.

Before the development of modern pesticides, people used various tools and natural chemicals to control pest populations. Some of the earliest documented pesticides include sulfur, salt, and heavy metals.

The synthetic chemical pesticides we’re familiar with today, however, emerged in the years surrounding World War II.

While organochlorine compounds like BHC and DDT were first developed in the 1800s, they weren’t widely used as pesticides until the late 1930s.

In fact, Swiss chemist Paul Hermann Müller only discovered DDT’s insecticidal properties in 1939 — a discovery that led him to win the Nobel Prize in 1948.

While DDT was popular until the early 1970s, it was eventually abandoned in favor of safer, more modern pesticides, such as organophosphates (also called the OPs) and a neonicotinoid known as Imidacloprid, which is now one of the most broadly used insecticides in the world.

Today’s pesticides look quite different from the original chemical pesticides:

In addition to breaking down quickly, being safer for the environment, and sparing non-target species, today’s pesticides are more advanced and targeted, acting precisely upon the pests they’re designed to control and providing fast, laser-focused knockdown.

Pesticide Formulations 101

pesticide formulations

Generally speaking, pesticides can be divided into the following formulations:

1. Liquid Formulations

Liquid formulations are some of the most common on the market and widely available in both the professional and DIY pest control space.

Depending on the product, liquid formulations may be concentrates, ready-to-use sprays (including emulsions and aerosols), or fumigants.


  • Penetrate surfaces effectively and leave ample active ingredient residue to kill pests.
  • Easy to use (especially ready-to-spray varieties)
  • Effective for residential applications.


  • Some mixtures require pre-measuring or agitation.
  • May leave visible residue on surfaces.
  • More expensive than other formulations.
  • Highly toxic and may require special site preparation and training.

2. Dry Formulations

Dry formulations included dusts, wettable powders, baits, granules, resin strips, pellets, and fumigant tablets.

Commonly used in urban pest management, dry formulations are highly effective pesticides that provide robust residual protection and can be applied to most surfaces without harming them.


  • Ready to use
  • Does not require mixing
  • Provides better residual protection, especially on porous surfaces, than many liquid concentrates


  • May “cake” and become less effective under moist or humid conditions
  • Requires experience to apply correctly
  • Can present an inhalation hazard to the person applying them.
  • Messy and may require the purchase of specialized application equipment, like bulb dusters

How Pesticides Work

All pesticides work differently, depending on the type and formulation.

Here’s a breakdown of the different types of pesticides and how each works to control pests:

Pesticide or AgentEffect
Acaricides, MiticideKills ticks and mites/kills mites
Algicide/BactericideKills algae/Kills bacteria responsible for causing disease in plants, or animals
FungicideKills fungi that cause mold, mildew, and plant diseases
HerbicideKills weeds
InsecticideKills insects and pest arthropods, including spiders
RodenticideKills rodents, including rats, mice, and ground squirrels
AdulticideKills pests in the adult stage of life
AttractantAttracts pests, including insects and vertebrates
DesiccantKills insects by degrading and dehydrating their waxy exoskeletons
DisinfectantDestroys harmful microorganisms, including viruses, bacteria, and mold
Insect growth regulator (IGR)Disrupts the reproduction and development of insects to control populations without killing them
Larvicide/OvicideKills insect larvae/kills insect eggs
PheromoneChemicals vertebrates and insects use to communicate with one another
Plant growth regulator (PGR)Encourages or interrupts plant growth
RepellentRepels pests, including insects, mites, and vertebrates
SynergistA class of chemicals used with insecticides to enhance the efficacy of the active ingredient
BiopesticideBiological organisms that work like a pesticide but aren’t synthetic chemicals
NematicideKills nematodes in the soil that kill plants

What Types of Pesticides Are Available?

types of pesticides

Today, there are three broad classes of pesticides available on the market. 

Here’s a brief breakdown of each:

Conventional Pesticides

Synthetic Organic Compounds

Synthetic organic compounds include chemicals like pyrethroids, carbamates, neonicotinoids, organophosphates, insect growth regulators (IGRs), and fumigant gasses, among others.

While the function of these chemicals varies, most work by disrupting the nervous system, inhibiting energy production, or disrupting development. 

Synthetic organic compounds are popular because most break down quickly and don’t build up in the environment, which makes them safer than earlier pesticide inceptions like DDT. 

Green Pesticides

Non-Synthetic Compounds

Non-synthetic compounds include botanicals like pyrethrum or pyrethrins, essential oils, and abamectins, all of which work by disrupting the nervous system. 

These pesticides remain, in many ways, similar to the original pesticides our ancient ancestors used to protect their crops. 

Sometimes referred to as “natural insecticides,” non-synthetic compounds are typically derived from plants. Natural pyrethrins (the active ingredient in pyrethrum extract), for example, are derived from the chrysanthemum flower. 

While non-synthetic compounds are widely considered safer than synthetic organic compounds, there are a few caveats to using them. 

For example, natural pyrethrins must be used in combination with synergist pesticides like piperonyl butoxide, since most insects that come into contact with pyrethrins can degrade the compound within their bodies before it becomes lethal. 

Combining the botanical insecticide with a synergist, however, blocks the enzyme reaction that allows the insects to recover from pyrethrins alone. 

Inorganic Compounds

Compared to synthetic organic compounds, inorganics are some of the oldest insecticides, although they remain in widespread use. 

These pesticides work by inhibiting energy production or disrupting or desiccating the pest’s exoskeleton. 

Also known as “minerals,” these compounds are mined from geological deposits in the earth before being mixed and refined to create modern pesticide formulations, including boric acid, sodium fluoride, diatomaceous earth (DE), and silica aerogel

While most inorganics kill pests much more slowly than synthetic organic compounds or non-synthetics, their benefit is that they offer long-term residual protection. Additionally, pests can’t become resistant to inorganics, which makes them unique in the field of pesticides. 

Advantages & Disadvantages of Pesticide Use

Pesticides are powerful, robust products that can help you control even severe pest populations.

That said, there are both pros and cons to the use of pesticides, and it’s important to consider both before you choose to apply them.

The Pros of Using Pesticides

  • Quick pest knockdown
  • Long residual protection
  • Effective population control
  • Targeted treatment for pests

The Cons of Using Pesticides

  • Some pests can become resistant to pesticides
  • Risk of harm to people, pets, and non-target species
  • Environmental risks, including runoff and pesticide drift 
  • Pests can learn to avoid certain pesticide formulations like baits
  • Some pesticides are highly regulated and controlled, and may not be available to non-professionals
  • Pesticides must be stored and disposed of safely 

While some pesticides can be used safely by non-professionals, it’s critical to remember that these are potent formulations that must be used exactly according to label directions.

If you’re ever unsure whether you want to use pesticides or not, contact a skilled pest management professional to consult with you on your pest issue. Call us at (844) 532-0076, and we’ll connect you with a professional pest management company in your area. 

They’ll be able to provide targeted recommendations to effectively remove pest populations while keeping you, your family, and the environment safe. 

How to Use, Dispose of, and Store Pesticides Safely

how to use pesticides safely

Follow these tips to ensure safety at every step of the pesticide use cycle:

1. Choose pesticides carefully

Before you choose a pesticide to use, consider a variety of factors to make sure you’re picking the right one. 

First, consider the type of surface you intend to treat – some stained or chemically treated surfaces may react with the chemicals in certain pesticide formulations, and some formulations, including oil-based concentrates, may stain or discolor porous surfaces. 

You’ll also need to consider the safety of non-target organisms, including pets and non-target species. 

If the active ingredient in the pesticide you’ve chosen is a threat to non-target organisms, find a way to secure the formula, such as within a bait station. 

Finally, consider the method of application and whether it’s suitable for your purposes. 

Dust formulations shouldn’t be used in high-traffic areas, for example, and fumigants often require you to vacate the home for a period of several hours. 

Read all label directions carefully to make sure you’re selecting the right formulation for your application. 

2. Pesticide handling and storage

Whenever you’re handling pesticides, be sure to do so carefully to avoid spillage and contamination. 

All pesticides should be clearly marked and secured in locking containers out of reach of kids and pets. 

Pesticide storage areas should be both dry and cool, with ample ventilation to prevent the buildup of pesticide fumes. 

Liquid pesticides should always be stored separately from dry pesticides like dust, baits, or granules. 

3. Mixing pesticides

Some pesticides can be mixed together to increase their efficacy, but it must be done carefully. 

Before mixing any pesticides, always read the pesticide product label and follow all directions exactly. 

To protect yourself during the process, wear chemical-resistant safety goggles, a mask, and rubber, polyethylene, or neoprene gloves to protect your hands. 

When lifting pesticide containers, use both hands to decrease the risk of dropping and spilling the container. Mesure pesticides carefully, and rinse all measuring cups or containers thoroughly afterward. 

4. Disposing of pesticides

Never dispose of pesticides by dumping them down the drain or throwing them in the trash. 

Instead, use all prepared spray mixtures according to label directions and then follow the disposal instructions on the label. 

While some products, like emulsifiable concentrates and microencapsulated formulas, can be disposed of in landfills or recycled, others require disposal by commercial pest management operations. 

Pesticide Laws

The use of pesticides is regulated in the United States by the Federal Insecticide, Fungicide & Rodenticide Act of 1947 (FIFRA) and the amendment made to that act in 1996 – The Food Quality Protection Act

While these federal laws set the ground rules for pesticide use and should be read by anyone using pesticides for commercial or residential purposes, it’s also important to familiarize yourself with relevant state laws that may be enforceable in your area. 

Need a Professional Pest Management Company? We Can Help!

While it is possible to use pesticides safely, you might learn about them and then realize that you just don’t feel comfortable with DIY pesticide use. This is normal. 

Fortunately, you have another option: reach out to a professional pest management company for help controlling your pest population.

At The Pest Dude, we work with an extensive network of pest professionals all across the country.

Call us at (844) 532-0076, and we’ll connect you with a team in your area!


To protect yourself during pesticide application, wear protective clothing, including a respirator or mask, coveralls, chemical-resistant gloves, safety goggles, and rubber boots. Depending on the location of the application, you may also want to wear knee pads.

The symptoms of mild or moderate pesticide poisoning include fatigue, headache, dizziness, vision changes, stomach cramps or diarrhea, weakness, chest discomfort, and muscle twitches.

Severe poisoning symptoms include unconsciousness, severe constriction of the pupils, muscle constrictions, difficulty breathing, and secretions from the mouth and nose.

Pesticide poisoning may be fatal and must be treated immediately.

The least toxic pesticides available include naturally derived compounds like insecticidal petroleum, plant-based soaps and oils, and Bacillus thuringiensis, a common microbial insecticide. 

These formulas are considered safe because they’re highly selective and only capable of killing a small number of closely related organisms.

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Author Bio: Zachary Smith

Zachary Smith is the founder of Zachary is a licensed pest control professional with 20+ years of hands on experience eradicating pests from homes and businesses. Zachary earned his Bachelor of Science from Cal Poly San Luis Obispo in 2002. He specializes in rodent and insect infestation management of structures and landscapes. His passion is to share his extensive knowledge with the world.

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