Insecticides: why not use them and what alternatives

Insecticides: why not use them and what alternatives

In the vegetable garden and in the orchard, we often encounter harmful insects, capable of irreversibly damaging the cultivated plants. The simplest and most intuitive answer to this problem is a frequent use of pesticide treatments to break them down.

This is not always a good idea: any insecticide is a substance aimed at eliminating forms of life and generally has negative effects on the environment. There are organic insecticides with a low environmental impact, but you should know that practically all treatments against parasites have contraindications.

Insecticide treatments should not be demonized: they are often the only solution to be able to safeguard crops. The important thing is, on the one hand, to be aware of the problems that can lead, on the other know and use the various alternatives which allow you to keep pests at bay without treatments. Among these, as we will see, there is the method of food traps, still too little known but really effective in many cases.

The problems of insecticides

Not always responding to pest attacks with insecticide treatments is the best solution, for various reasons.

The first is obvious: ecological damage. We talked about it in more detail in an article dedicated to the risks associated with pesticides: insecticides can pollute the soil, the aquifer, the air. They are a risk to human health and come to the table on fruit and vegetables.

The insecticides allowed in organic farming are not exempt from this kind of problems, even if they are certainly less aggressive than other molecules deriving from chemical synthesis. So let's highlight a few problems that the insecticide can bring even in an organic garden.

Pesticides are not selective

The great majority of pesticide treatments are non-selective and they can claim victims not only among parasites but also among beneficial insects.

Rightly speaking of insecticides, we are concerned about the dangers to human health, but it is also good to consider other forms of life that can be put at risk by treatments.

There are species that are of fundamental help for the plants we grow. The most cited example is that of bees, fundamental for the ecosystem. To them are added other precious species, such as ladybugs. In general, biodiversity is a wealth for the ecosystem in which we grow and helps us to keep it healthy and prevent many problems, as explained in the article on the resilient because biodiverse garden. The less pesticides we use, the better biodiversity will be safeguarded.

Generations of resistant insects

You also need to know that many insects are able to develop resistance to the active principles of insecticides over time, therefore intervening too often can create generations of insects that tolerate the treatment. This forces the grower to always find different treatments, varying the molecules, or to increase the dosages.

The insecticide is therefore a remedy that has a waning effectiveness: the more it is used, the less useful it is to solve. Other methods, such as food trapping, however, are not affected by this effect.

How to use less pesticides

In order not to run into the problems we have talked about, it is good to make a limited use of insecticide treatments. By cultivating organically we must not feel absolved: products such as pyrethrum can still cause damage and kill bees.

We must therefore always act with the aim of doing as few treatments as possible, trying to prevent the problem rather than cure it later. Here some ideas applicable immediately in your vegetable garden or orchard.

Alternatives to insecticides

There are alternative strategies to defend our plants without pesticides. They cannot replace the use of treatments in every situation, but they certainly are a valuable aid in reducing its use, using pesticides only when strictly necessary.

Here are five concrete ideas:

  • Macerated repellents. Some plant substances are unwelcome to insects, such as essences of garlic, chilli, wormwood, nettle, rhubarb. We can macerate these plants and obtain natural treatments capable of driving away insects. This method requires a lot of time and consistency of application, it lends itself to small-scale cultivation.
  • Traps for catching. An excellent idea to eliminate insects without spreading poisonous substances in the environment is to capture them through traps. Glue, pheromone or food color traps can be used. The first type is not selective, so it can reap innocent victims and capture bees, so the sexual bait of the pheromone or the food one is preferred. Tap Trap-type food traps are particularly interesting because they are simple to make and cheap.

  • Natural antagonists. If there are predators in the environment, the parasites will have a short life. We can encourage the presence of natural antagonists or even release them into the environment. This method is complex and requires knowledge and investment to avoid dispersing antagonistic insects. It works well in the greenhouse, in general it is useful for professional cultivation.
  • Rock powders. There are mineral powders such as kaolin, bentonite and zeolite that can be sprinkled on leaves and fruits, creating a patina that bothers phytophagous insects and discourages them.
  • Nets exclude insect. A mechanical method is to protect plants with nets that do not allow insects to reach them. In some cases it is a good system, albeit costly in terms of labor and materials.

Timely monitoring and intervention

One way to use fewer insecticides is to be timely: if you intervene when the parasites are few, a light treatment may be enough to keep them at bay and stop their spread. In particular, for this purpose it is important to intercept the first generations, since insects are able to proliferate rapidly. Once the parasite has reproduced and settled, many more treatments will be needed to eradicate it.

For immediately detecting the presence of a harmful insect is important to monitor, which is implemented with traps. Also in this case we can do it with chromotropic, sexual or food attractants. I have dedicated a specific article to the use of traps to monitor, you can refer to that to deepen the topic.

Monitoring is essential especially in the orchard. Having mainly annual plants, the garden has cultivation cycles that last only a few months, while in the orchard, on the other hand, as the fruit trees are perennial, the settlement of insects and their subsequent reproduction can be a more persistent problem. Traps in the orchard are useful in catching different types of harmful pests, from moths to fruit flies.


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