Natural insecticides: the biological defense of the garden

Natural insecticides: the biological defense of the garden

Natural insecticides: the biological defense of the gardenMatteo Cereda2020-08-14T17: 52: 28 + 02: 00

Let's find out together how to protect the plants in our garden from insects and parasites using allowed methods in organic farming, without polluting the land we grow and obtaining healthy vegetables.

In this section of the site you will find a guide dedicated to natural insecticides, integrated pest management and methods to prevent and combat plant parasites. Lots of tips for a biological defense of cotlivations, which is healthy and respectful of the environment and the health of those who will eat the vegetables.

The main biological insecticides

Insecticides are all those products that serve to rid the garden of harmful insects. If we want to cultivate a healthy vegetable garden or orchard we must avoid using chemical pesticides, which often have very negative effects on human and animal health, as well as being polluting. So let's go and discover with these guides some products of completely natural origin that can be used to defend crops and are also allowed under organic cultivation.

Among the possible biological anti-parasitic treatments we can divide the insecticides in the strict sense, which are toxic substances that can kill parasites, such as pyrethrum, while other substances mainly have a repellent function and keep insects away from vegetables without causing them damage. but merely chasing them away. Below we see the actual insecticides.


Neem oil

Bacillus thur.


Macerated nettle

Soft soap

White oil

Garlic decoction

Sweet orange


Characteristics of insecticides

The treatments that are used to defend the vegetable garden are divided into two groups: insecticides or pesticides are the pesticide treatments that fight insects and which we are talking about on this page, while fungicides are those that serve to defend crops from mold. and mushrooms.

Pesticides act by contact when they are not absorbed by the plant and work only if the substance directly affects the insect, translaminar when they are able to pierce the leaf and act on both pages. If, on the other hand, they are products that are absorbed by the plant, we speak of systemic pesticides. Systemic pesticides are the most dangerous for humans: they are absorbed and accumulated by the animal and plant organisms and are not allowed in organic farming.

In the organic garden, only contact or cover pesticides are used, which remain external to the plant. The substances must also be of natural origin, synthetic chemicals are not allowed.

Warnings and waiting period

According to the law on chemicals and pesticides in general, certain information must appear:

  • A symbol indicating the degree of toxicity (the highest is the skull which means deadly, the toxic cross, the moderately toxic square).
  • The active ingredient of the product.
  • Indications in case of intoxication.
  • The instructions for use and any toxicity on some plant species.
  • The days for which you should not enter the treated area.
  • The days of shortage, that is the minimum time that must elapse between the phytosanitary treatment and the food consumption of the treated vegetables.

Natural insecticides from the organic garden

  • Pyrethrum: contact insecticide.
  • Neem oil, insecticide and non-toxic repellent for humans.
  • Bacillus Thuringiensis, harmless to humans, is a bacterium that kills lepidopteran larvae by blocking their digestive system.
  • Macerate of nettle, which contains formic acid.
  • Garlic decoction or macerated (squeezed garlic left to infuse), excellent against aphids as an insect repellent.
  • Marseille soap, always useful for removing aphids and cleaning the honeydew.
  • Propolis. They have an insecticidal function and it seems that they also act as fungicides.

Other vegetable macerates against insects

  • Quassio, decoction of bitter quassia bark, aficid and repellent of many parasites.
  • Absinthe, to defend the garden from aphids, noctuids and ants.
  • Chilli macerate, repellent thanks to capsaicin.
  • Rhubarb macerate, which contains oxalic acid.
  • Macerated tansy, against spider mites, aphids and noctuids.
  • Tomato macerate. Useful to remove cabbage thanks to solanine.
  • Mint macerate. To drive the ants out of the garden.
  • Macerated fern. It is used against cochineal and aphids.

For more information on herbal preparations, you can read the article dedicated to macerates and decoctions useful for the organic garden.

Biological control and integrated defense

In addition to the use of insecticides, there are other methods to defend the garden without treatments. There are friendly insects that can help us fight garden pests and completely natural systems of integrated pest management to protect the garden from any problem. So welcome ladybugs and other animal friends who in a system rich in biodiversity act as a natural limiter of parasites by preying on them.

Another valid method of defense of the garden is that of traps, which can be used both for monitoring and for the mass capture of parasites.

The use of appropriate plant associations is instead a nice system to exploit the natural qualities of plants in order to create synergies that help keep enemies away.

Then there are physical methods of hindering insects, such as the covering with anti-insect nets or with non-woven fabric, but also rock powders such as kaolin and Cuban zeolite.


The biological struggle



Rock powders

An in-depth reading

We would like to point out a text published by Terra Nuova which is very useful for orienting yourself on how to defend the garden from pests and diseases without poisoning it with chemicals: defend the garden with natural remedies.

  1. luisa hanozet3 May 2016 at 15:30

    always very interesting news. Thanks

  2. Mella15 May 2016 at 17:12

    I would like to point out that pyrethrum is the plant from which cyfluthrin is extracted, a well-known and very common pesticide. I would never include it in organic methods, a Bayer spray might as well :(

    • horticulturist17 May 2016 at 8:42

      Hello Mella, pyrethrum is a natural insecticide and is allowed in organic farming (this is a fact). It is definitely different from a chemical pesticide spray. Then, as we explain in the article dedicated to pyrethrum, this too can be harmful to humans and useful insects and has a shortage period. There are natural methods with less impact. In some cases the pyrethrum is very useful.

  3. Viarengo Luigi4 September 2016 at 9:19

    Thanks for your advice, next year I will put them into practice

Comments are closed.

Video: How to make Insecticide, Pesticide, Fungicide, Antibiotics Miracle All in one Solution.