How to Use Pesticides in Your Garden?

Translated by Nick R

Just as there are homemade insecticides to eliminate various pests in the garden, there are also chemical pesticides for the same purpose. The difference lies in that you can find a wider variety of these products depending on the type of pest and with compounds that act almost immediately.

However, there are risks since pesticides can be toxic to plants, animals and people if you don’t use them correctly. That is why in this blog I want to talk about these products, their varieties, characteristics, and how to take care of them.

What are pesticides?

Pesticides, also called herbicides are chemical substances used for the control, prevention or destruction of pests in agricultural plantations. In addition, they are also used as a vegetable regulator, defoliant or desiccant.

These pesticides also act against vectors (living organisms) that carry diseases which affect humans and animals. They fight any type of plant or animal that harms the production, processing, storage, marketing or transport of human and animal food, agricultural products and wood products.

They are also employed in animals, either internally or externally, to combat insects, arachnids or any pest that may affect them.

The safety and effectiveness of pesticides depend on knowing the type of pest you are treating and identifying whether or not the product is suitable for the crop. In addition, you should recognize the risks of applying pesticides, the required doses and the established norms for pesticide management according to the region.

Do not forget to always check the information on the product label, precautions and warnings. If you have any doubts, it’s advisable to consult with the sellers or someone specialized and pay close attention to the symbols also found on the labels:

In this way, you’ll be able to avoid serious inconveniences due to pesticide mishandling. This product cannot be taken carelessly.

These products are regulated by the U.S. Environmental Protection Agency (EPA) to ensure the minimum potential risk of pesticides to humans, animals and the environment. It covers pesticides used in the U.S. as well as those exported to other countries. However, there are several regulatory bodies depending on the country you are in.

Besides the above, pesticides have benefits and contraindications important to mention. Concerning the benefits, we find that:

  • Pesticides help control diseases such as malaria, typhoid, yellow fever, and others.
  • They promote the creation of new jobs since, in the case of a large crop, manpower will be required to apply the product.
  • They are used to reduce the fruit density or to avoid premature fruit drop.
  • Applying pesticides on crops before or after harvest can help preserve the product during transport and storage.
  • The use of pesticides can reduce production costs so that, in the case of food, they are more affordable for the end consumer.
  • It also helps to protect people’s homes from termites, disease-carrying rodents, insects and all kinds of unhealthy pests.

Regarding contraindications, we can find that:

  • If they are not used properly, they can cause damage to the health of those in contact with the pesticides. For example, when adequate protection is not used to handle these chemicals, some residues can enter the organism through various access routes.
  • Without sufficient precautions, pesticide residues can leach through the soil into important water sources and contaminate them.
  • Just as pesticides kill harmful insects, they can also kill beneficial insects.
  • Some animals may also be exposed to pesticide residues and experience health problems.

Classification of pesticides

As mentioned above, pesticides can be used to combat multiple pests in different products. These products are grouped in order to make their application organized and effective.

In this blog, we’ll focus on their application for the plant health group, which is known as agrochemicals or phytosanitary products. Here pesticides are classified according to the type of pest to be treated. We find then:

  • Insecticides: control insects such as aphids.
  • Acaricides: act against mites.
  • Nematicides: fight nematodes, which are a kind of small worms that live in the soil.
  • Fungicides: specific for fungi.
  • Herbicides: in charge of controlling weeds.
  • Molluscicides: combat caterpillars and snails.
  • Insect attractants and repellents: traps and pest repellents.
  • Rodenticides: act against rodents.
  • Avicides: to eliminate or repel birds.


Pesticides are made up of 2 ingredients. The first is the active ingredient (AI) and the second is called the inert ingredient.

Pesticides can contain from 1 to a maximum of 3 active ingredients. These ingredients are the chemicals used to control pests, but they are found in very small doses, so they cannot be used alone. It’s necessary to mix them with inert ingredients.

Inert ingredients are those chemicals, compounds, and other substances such as foodstuffs and natural materials which together with the active ingredients create pesticides.

These ingredients can be toxic, so they must be studied in depth to prevent harm to people and the products in which the pesticide is used. This study is carried out by the EPA.

Some of the functions performed by inert ingredients to ensure the efficacy of pesticides are:

  • They serve as a solvent so that the AI can penetrate the leaf surface.
  • Facilitate pesticide application.
  • Prolong the pesticide’s shelf life
  • Contribute to improve safety for the person who applies the product as research concentrates on eliminating the threats of their application.
  • Protect the pesticide from being degraded by sun exposure.

The pesticide labels must show the total percentage of active ingredients and, in some cases, the percentage of inert ingredients for your knowledge. Therefore, you should always check all the information on these labels, so you can make sure that it isn’t a toxic product.

Application of pesticides

Before explaining how you can apply these products, you should be aware of the toxicity levels, access pathways in crops and how you can protect yourself while handling pesticides.

Considerations before applying pesticides

Toxicity band

This is a categorization established by the WHO and is color-coded according to toxicity levels. This toxicity must be calculated so that classification is feasible. A method known as LD50 (Lethal Dose 50%) is used to make this calculation. The LD50 is the dose needed to eliminate 50% of a sample population.

The lower the LD50 value the higher the toxicity, which means that the lower the required dose, the more dangerous the pesticide is. The dose is expressed in mg/kg live weight and together with the AI, you should keep in mind this data when using pesticides.

Toxicity categorization established by WHO

Routes of entry into the organism

For pesticides to act on plants and eliminate pests they must have different routes of entry. Sometimes, the way they enter determines the mechanism of action.

  • Ingestion: here the pesticide must be consumed by the pest, so it must have attractive substances to achieve the objective. It can be powder, bait or liquid.
  • Contact: here pesticides act on the pest’s body and cause its death. They can be applied by spraying, smoke or aerosol.
  • Inhalation: in this case pesticides are gaseous, and the vapors they emit are inhaled by the pests, repelling or eliminating them.

Protection for pesticide handling

The following aspects must be considered to be able to properly apply pesticides on your crops.

Receive adequate training for proper handling of pesticides. It’s also recommended to minimize the exposure time to the product. Avoid consuming food near the area where you are applying the pesticide.

It’s essential that you use personal protective equipment such as respirators adapted for chemicals, rubber gloves, a waterproof suit, plastic apron, rubber boots, a wide-brimmed hat, and ocular equipment such as goggles and face masks.

This may seem a bit excessive but remember that these pesticides can come into contact with our organism through the respiratory, oral, ocular, cutaneous and digestive tract (in the case of consuming contaminated products). They could cause serious damage to your health and the health of those around you.

How to apply pesticides?

Now that you know the previous suggestions, I’ll mention the ways in which you can apply these products to your crops.


This is the application of gas or liquid on crops. It is effective in controlling insects, fungi, weeds and nematodes, but it can be toxic so use protection as needed.


It’s used to apply powdered pesticides, and it is functional for small crops. In large extensions, a homogeneous application could be difficult to achieve.


It’s done by generating small droplets suspended in the air and fall on the crops in form of a mist. This method can be used to control mosquitoes and is not recommended for very large crops.


The pesticide is applied to the soil by means of injectors, which helps to control ants.


This is the most widely used because it is practical and efficient. You can use sprayers to reach large extensions without wasting the product. Millions of droplets are scattered to reach the crop and act to kill the pest.

It’s imperative that you use adequate protection such as gloves and masks to prevent the product from affecting your health.


The pesticide is applied to the soil by means of injectors, which helps to control ants.


It’s the most used because it is practical and efficient. You can use sprayers to reach large extensions without wasting the product. Millions of droplets are scattered to reach the crop and act to kill the pest.

It’s imperative that you use adequate protection such as gloves and masks to prevent the product from affecting your health.

Pesticide presentations

In markets, we can find several pesticide presentations, either liquid or solid.

Solid pesticides

  • Powders: easy to apply and for small crops.
  • Baits: also known as attractant traps.
  • Granules: similar to powder, but the particle size is larger.
  • Pellets: similar to granules, but particles of the same size and shape.
  • Wettable powders: a finer powder similar to talcum powder that requires constant shaking to stay diluted in water.
  • Dispersible granules: similar to wettable powders but easier to mix.
  • Soluble powders: when in contact with water they can form a true solution.

Liquid pesticides

  • Emulsifiable concentrates: contain AI dissolved in petroleum-derived solvents and have a milky appearance.
  • Suspensions: concentrated or flocculent: AI crystals suspended in water.
  • Solutions: AI is dissolved directly in water or other solvents.
  • Inverted emulsions: AI soluble in water and accompanied by other inert ingredients forming an emulsion.
  • Microencapsulated: AI is contained in a water-dilutable microcapsule.


Now you know the benefits and counter-indications of pesticides, and also the types and forms of presentation that you can find in the market. I have mentioned those essential recommendations for the handling of these products.

Also, as I’ve mentioned, it’s crucial that any product you purchase is approved by the relevant entities, such as the EPA.

Do not forget always to read the labels, instructions, uses, toxicity levels and all the information about the product.

I hope all this information has been useful to you and has clarified any doubts you may have about pesticides. Remember that you can use them in your crop following the pertinent recommendations and care.