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Beneficial Insects in Organic Horticulture: A Resource Worth Preserving

Beneficial insects play a vital role in biological pest control, offering a natural solution to mitigate the damage caused by harmful pests in agriculture. However, their populations are at risk due to the indiscriminate use of chemical pesticides. This article explores the importance of these insects and strategies to conserve them.

by BioGrow

Useful insects are the great allies of biological control in agriculture. These are antagonistic insects, ideally already existing in the ecosystem, which have the ability to naturally contain and control the action of harmful pests on crops. Unfortunately, the indiscriminate use of chemical pesticides over time has disrupted the balance of the agro-system, decreasing the presence of these “good insects” in our fields. To achieve collective benefits, we should instead try to enhance these existing resources by creating the ideal environmental conditions for their settlement.

In this article, we try to understand how beneficial insects act and what are the main species existing in our country.

The advantages of beneficial insects

First, let’s understand the advantages of using beneficial insects in agriculture and in the environment in general. With natural antagonists, the use of pesticides is avoided, as they keep pests within a tolerance threshold. This, as can be easily understood, reduces damage to crops.
This type of biological control strategy aims to restore the natural balance of the ecosystem by reintroducing native or cosmopolitan species.
Moreover, thanks to their high selectivity, beneficial insects target only the intended pests. This way, they do not harm other harmless species.
Another advantage is that, thanks to modern biotechnologies, it is possible not only to safeguard the presence of native insects but also to introduce new ones through artificial releases in areas where they are no longer present or insufficient. The topic, moreover, is subject to continuous research and scientific studies.
Live insect families can be found online, safely shipped to various locations (such as here). Furthermore, you can also find interesting insights on the subject, like this.

Predatory Insects, Mites, and Nematodes

If we have so far spoken in a generic way about beneficial insects or natural antagonists, let us now make a small distinction. There are three types of beneficial insects:

  • Predatory and parasitoid insects;
  • Mites;
  • Nematodes.

Let’s see specifically how they work.

Predatory and parasitoid insects

Hoverfly, useful insect
The overarching category of insects is divided into predators and parasitoids. Predators are species that completely devour the harmful parasite, such as aphids and mites. Their action is able to keep the populations of prey insects within acceptable levels. Crop damage, consequently, will be minimized. Among the predatory insect species of greatest agronomic interest, we mention ladybugs (Adalia bipunctata and septempunctata), which we have already discussed, and hoverflies (family Syrphidae, subfamily Syphinae). The use of hoverflies has proven to be very effective in biological control in protected crops (greenhouse). They are useful insects, resembling small bees. They have an important function as pollinators and prey not only on aphids and mites but also on: scale insects, lepidopterans, and beetles like Colorado potato beetle and ants. Parasitoid insects, on the other hand, behave in a more complex way, as they can be carnivorous only in the initial larval stage. As adults, these insects mainly feed on sugary secretions they find.
Among the beneficial insects of this category, small hymenopterans, such as Ooencyrtus telenomicida, have attracted much scientific interest. These small insects are capable of parasitizing the eggs of the dreaded brown marmorated stink bug Halyomorpha halys. The brown marmorated stink bug is causing significant damage in Italy, as a non-native species alien to our ecosystem. It is therefore becoming increasingly dominant and dangerous. The best solution to solve the problem at its root is the introduction of beneficial insects. Let’s see if science will lend us a hand.


Useful mites in organic agriculture belong to the class of Arachnids. The families of greatest interest are: the Phytoseiidae, the Stigmaeidae, and the Trombidiidae. Beneficial mites feed on both insects (especially aphids and scale insects) and other phytophagous and harmful mites.
Among the species of greatest agronomic interest, we mention:

  • Amblyseius spp.;
  • Hypoaspis aculeifer;
  • Macrocheles robustolus;
  • Phytoseiulu persimilis.


Nematodes are microscopic parasitoid organisms. Their peculiarity is that they are highly selective. They feed on and reproduce only on the larvae of host insects and are harmless to mammals, birds, other beneficial insects, and earthworms. The active forms of entomophagous nematodes reach the larvae of harmful insects only in the presence of high soil moisture. After reaching the larvae, they penetrate their bodies and parasitize them. The biological cycle ends with the emergence of new forms from the emptied shells of the target larvae.
We have seen the use of entomophagous nematodes (or entomopathogenic) in the fight against the Colorado potato beetle and the black vine weevil. Nematodes can be easily purchased (such as here).
The main species are:

  • Steinernema spp.
  • Heterorhabditis spp.

How to Attract Beneficial Insects to the Garden

To attract as many beneficial insects as possible to our organic garden, agricultural techniques can be implemented.
The best-known method is to create shelters, small handmade houses where insects can overwinter. A nice insect house ready for use can be found here.
In general, attracting beneficial insects involves ensuring a certain plant diversity in our soil, adequate sources of nourishment (nectar, pollen, honeydew), and optimal humidity conditions. The use of ecological infrastructures, such as hedges, tree belts, ground covers with refuge and trophic functions, is also important.

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