Agroecological strategies to prevent orchard and garden pests and diseases

First of all, before addressing the different control methods, it is necessary to define what we understand by pest .

When a living being, insect, fungus or another causes damage to our plants, the first thing we look for is how to eliminate it. However, this does not guarantee that the same or other pests will reappear in our garden.

All living organisms are a necessary part of nature, each one of them has an irreplaceable function. Now, when for some reason any of them reproduce disproportionately, that is when problems appear, and they can cause serious damage to our crops. This is common in agriculture, but it does not usually happen in natural ecosystems, because the populations control each other reaching a certain balance over time, without suffering large fluctuations.

A pest is, therefore, a living being that has been left uncontrolled, reaching a high population level, thus breaking the balance with nature. It must be clear that not every living organism present in our garden is a pest, since many of them are excellent biological controllers, such as “vaquitas” or “ladybugs”, insects belonging to the coccinellidae family, which perform a very efficient control of aphids.

When making an organic garden, what we must try to achieve is to create the best conditions so that all its elements are in balance, and that the same living beings can control each other.

We also advise you which organic seeds to use , the best planters, growing boxes and tables for your garden and essential books to learn everything about organic gardening .

Agroecological methods for pest control

There are various pest control methods, the main ones for the organic garden are:

1.- Mechanical pest control

It is a simple technique that consists of manually collecting larvae, insects, snails, butterflies, slugs, etc. to destroy them. It is a laborious technique, but if we spend a few minutes each day observing our garden carefully, we can detect problems when they are just beginning, and therefore it will be easier to correct them.

2.- Cultural control of pests

It is the use of agricultural practices, aimed at preventing or controlling pest attacks.

Some of these techniques are:

  • Eliminate sources of infection, such as crop residues, composting or burning if the presence of pathogens is found.
  • Crop rotation and association, to interrupt the biological cycle of the pest.
  • Adequate distancing from the species to be cultivated.
  • Cultivation of resistant varieties.
  • Good management of irrigation water.
  • Installation of biological fences.

3.- Ethological control of pests

It is a method that uses the reactions and behavior of pests to control them. With this method, attractive or repellent traps are used.

attracting light traps-Attracting light traps

During the night many insects are attracted to light, with violet light or “black light” being the most effective. Once attracted, it is made to fall into a trap, which can be a container with water or oil.

The recommended distance between traps is 50 cm.

The light traps should be placed at a distance no greater than 5 m between them, and preferably, on the perimeter of the garden.

-Yellow attractive traps

yellow trapsThey are very effective especially for whiteflies, aphids and thrips.

It can be easily manufactured, assembling a kind of little yellow wooden sign (it can be achieved by gluing a paper of this color) of 30 by 30 cm, hung at a height of 50 cm vertically.

Some transparent and sticky substance should be placed on this poster, so that the insects are trapped, such as honey.

Another option is to paint the inside of a shallow can, bright yellow. Hang the can on a piece of wood and add half the water to it. The insects will be attracted to the color and die when falling into the water.

-Attractive traps with food

It consists of cheating with nutritious substances, such as sugar and beer, to attract insects. This technique is recommended for the control of snails and slugs, for which the beer and sugar must be placed on a plate at ground level.

4.- Biological control

It is the reduction of pests through the action of natural enemies. These can be parasites, predators, or pathogens.

Biological control is natural when man does not intervene, artificial when man participates in the breeding and release of controllers.

-Parasites orchard parasites

Most parasites are small (wasps, flies, etc.). These need other insects (host) to reproduce and fulfill their biological cycle. They lay their eggs in the host insect, which upon hatching expels a larva, causing it to die.


orchard predatorsIn nature, many animals feed on others and also on eggs, larvae, pupae or adults.

Among the predators we have: reptiles, toads, birds, mites, insects, beetles, etc.

A great predator is the Lacewing ( Chrysoperla externa ). It is a delicate insect, its body and wings are hyaline green and bright, its wings folded vertically on the sides of the abdomen have the appearance of a fine lace. Size from 1 to 2 cm. Females lay their eggs in small groups, at the end of a thin 1 to 2 cm peduncle.

They are easy to breed, the leaves are taken with the small eggs and they are placed inside a bottle covered with a mesh or tulle that allows oxygen to pass through. As soon as they hatch, the larvae must be released into our garden. They are very effective for the biological control of aphids, mealybugs, queresas, butterfly larvae, etc.

Below are pictures of lacewing eggs, larvae, and adults:


Other large predators, which we mentioned previously, are “ladybugs”. They are very efficient in controlling aphids (adults and eggs), whiteflies and larvae of small butterflies.




Among the most important pathogens are viruses and bacteria, which act by causing discomfort to insects, larvae, locusts, queresas, weevils, causing massive death.

The best known bacteria is the bacillus Bacillus thuringiensis , which is currently found commercially under the names: Dipel, Thuricide, Bactospeine, which act biologically without polluting the environment. They receive the generic name of Bioinsecticides .

Control of diseases in orchard and garden

There are many diseases, caused by various fungi, bacteria or viruses that affect plants causing damage to crops and stored vegetables.

When is a plant sick?

  • They look yellow or other colors that are not normal
  • Withered or drooping
  • Weak
  • With rotten fruits

When a plant is in an advanced stage of disease, it can no longer heal, so prevention of them is extremely important. We must take all the necessary care so that favorable conditions for the development of diseases do not exist in the garden.

Some measures for the preventive control of diseases are

  • Crop rotation: Vegetables from the same family should not be planted on the same land. Diseases can remain in the soil from one year to the next.
  • Resistant varieties: In many vegetables there are varieties resistant to one or more diseases.
  • Do not leave vegetable remains: Always use vegetable remains to prepare organic compost. If they are left in the field they can spread diseases to the plants of the next season.
  • Control insects: Insects can also transmit diseases like viruses.
  • Weed control: Weeds help create a humid environment that favors the development of diseases.
  • Take care that the water does not stagnate: The water must not be stopped in the furrows. If this happens, you have to make exit channels.
  • Do not plant too dense: Especially in humid areas the plants should not be too close to each other, because it favors humidity and the development of diseases.
  • Protect the fruits: With guardians or covers you can protect the fruits that by their weight are close to the ground. For example, tomatoes, cantaloupe, squash, or watermelon.
  • Use good quality seeds : The seeds can also bring diseases that will later appear in the crop.

Images DIACONIA, Wiki commons

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