Quels sont les insectes nuisibles dans la culture du cannabis ?

What are the harmful insects in the cultivation of cannabis?

02/09/22Lu en 6mn
  • There are many harmful natural plagues that can affect the cannabis plant, such as fungal diseases, phytovirus or harmful insects.
  • After having treated the first two subjects recently in depth, we will now be interested in the different types of pest insects which are capable of attacking our cannabis crops, and of leading the partial or total loss of the harvest.
  • During this article, we explain to you what insects can potentially make their appearance within a cannabis culture, we also tell you what prevention measures to put in place to limit this phenomenon, and especially what are the effective solutions To get rid of each of them. Follow the leader !


  1. What are the harmful insects in the cultivation of cannabis?
  2. The best prevention measures to apply to limit their appearance on the cannabis plant?
  3. Optimal solutions to eliminate harmful insects from cannabis 


What are the harmful insects in the cultivation of cannabis?

Cultivators already having some experience in the cultivation of cannabis plants, certainly already know most of the pest insect species which are mentioned here, because they will probably have already been confronted with some of these harmful phenomena within their garden.

We are sure that parasites such as mites, better known under the Red spider nameor different species of harmful flies such as miner fly or the White fly (Aleurode), like the ants, THE aphids, THE thrips, THE tracks, THE cochets, as well as nematodes are not so foreign to your dear cannabis cultures.

Red spider

What is commonly called the red spider, are in fact microscopic insects which in reality are simply mites. Red spider appears most of the time in cannabis cultures indoors, when the humidity level as Temperatures are high.

These parasites feed on aspiring the sap of the leaves by sucking, which causes many bites on marijuana plants. The spread of this harmful phenomenon can be rapid, and can destroy your harvest as soon as possible. This is the reason why we must react without delay ...

The different symptoms are easily identifiable, because these parasites leave traces of their meals behind them, through multiple bites which have the appearance of Small white dots on the upper surface of the leaves. These symptoms can be confused with nutrient deficiencies, however confusion is less important than with certain parasitic fungi.

These mites use the underside of the leaves to nest their eggs and the larvae, it is clearly their privileged place for their reproduction. As they only measure only a few millimeters, it is not easy to perceive them with the naked eye.

These spiders are not red in fact, as their name indicates, because their coloring is closer to brown and orange than red. As the infestation progresses, we will see an important training of Spider webs On plants, like different more and more dense cocoons, which is a sign of a total infestation of your culture.

If you reach this critical stage, without any curative action performed beforehand, then there will be no treatment based on insecticide products with formidable efficiency to remove these spiders permanently. So, you will have no other choice than to stop your culture completely, to proceed with a total disinfection of your space, in order to start your favorite activity in more conducive conditions.

The miner fly

The miner fly is a gourmet of the plant world, because these flies are selective and do not affect all varieties of cannabis in the same way. The miner fly has this characteristic name, since after having placed its eggs inside the vegetable tissues of the leaves, the larvae dig tunnels within the latter. This is clearly the key moment when you will quickly need to react to save all cannabis plants that adorn your garden.

You can perceive what strongly resembles Small galleries on the leaves, Through different brown lines, which characterizes the precise moment when the larvae prepare their tunnels within the plant tissues of the foliar mass. It is very simple, these flies devour all of the plant material that presents itself on the way, we can also observe small lesions generated by adult flies.

As far as possible, it is necessary to always give great consideration varieties of the best quality cannabis seeds you are going to buy.

Cultivators with a fairly short experience in the cultivation of cannabis, are not aware that these different species of pests are most often attracted by terpenes and flavonoids of cannabis plants, which are concentrated in the delicious and thick heads. resin trichomes.

The white fly (aurode)

The white fly is far from being the worst of predators for the cannabis plant, because its action consists of suck the sap present in the leaves To eat. The bad side of things is that it will gradually weaken the immune defenses of the plants.

It is quite easy to notice the presence of white flies within crops, because as soon as you touch or handle the marijuana plants, the latter fly above and we can clearly distinguish their white color.

Another indicator characterizing their presence is also that some leaves will turn yellow because of the chlorotic process generated by the significant sap disability within plant tissues. You can also see as a kind of molasses, which is the fruit of the secretion of these predators, with also the presence of a fine white dust on the back of the leaves.

The ants

At first glance, ants do not seem to be serious predators for cultures, however it is better to detect them and quickly get rid of their presence. Ants have a certain attraction for cannabis plants, because of the honeydew produced by aleurodes and aphids.

Ants feed on the honeydew of the plant, which protect the aphids, by giving them the possibility of reproducing in number in peace, since the traces of their presence are thus erased behind them.

We can also add that ants set up an aggressive technique to enter the plants of the plants, as they can dig small galleries Within different parts of the plant structure, which could alter the root system, such as the circulation of water and nutrients between the roots located in the soil and the aerial part of each plant.


The aphids seem to be small sympathetic living organisms from afar, however, they have significant mobility as a rapid reproduction speed (from 40 to 120 larvae per day). They are incredibly tiny because they only measure between 1 to 10 millimeters, as much to say that they are almost imperceptible to the naked eye.

Aphids can have a coloring green, white, red Or black. Like red spiders, they feed on the sap contained in the leaves. Once these last detected, it is necessary to act quickly, because these parasites have the capacity to quickly infest your cultures.

Some visual signs highlight their presence, because you will perceive yellowed And drying, because the latter establish their colonies under the leaves or stems, by secreting a substance called honeylat.

As we mentioned in the previous paragraph, this honeydew which is a characteristic typical of sucking insects feeding on vegetable sap, the latter strongly attracts ants, something which must ultimately attract your attention.


Thrips are parasites that frequently attack cannabis plants, and which it is generally not easy to get rid of. The latter have a production potential which is also fast. You will notice their presence, thanks to Silver timber traces that they leave on the surface of the leaves after their passage.

You will see a few times too points, who are their stools, not to be confused with the bites of red spiders which are much more numerous. THE leaves become brittle As the infestation advances in time, because the thrips eat with the chlorophyll of the latter.

An excellent method of simple detection for thrips is to place adhesive traps just above the marijuana plants, because some of them will necessarily be trapped by the bright yellow color of this device. You will have the certainty that an infestation of Thrips is underway in the heart of your interior garden.

The caterpillars

The caterpillars represent a real danger for our interior and outdoor garden, because once the adult butterfly has placed the eggs on the plants, which will give birth to many larvae later, you will quickly observe the consequences of their Insatiable and destructive appetite on the different plants.

These insects are very voracious of vegetable matter, because they eat continuously until they reach their maximum size. The next step is the constitution of their cocoon, to finally give birth to the chrysalis, which is the ultimate evolution before attending the birth of the butterfly. Even if it is quite easy to perceive the presence of adult caterpillars, this would concretely mean that the latter's infestation is substantial.

This is for what if you see tiny Translucent and yellow eggs on the underside of the leaves, with also small black excrement and traces of bites, then you have to set up an action plan to eliminate them as quickly as possible. The caterpillars are also capable of entering the heads in training, which can cause the appearance of pathogenic mushrooms on them.


Cochets are tiny pests that attack marijuana plants both indoors and outdoors, the size of which can vary from 1 mm to 1 cm, and whose coloring is gray to brunette. It exists near 8000 species in total, its reproduction is rapid because it can lay between 500 and 2000 eggs both, knowing that the same individual realizes several cycles of the same type during a year.

Cochets are therefore quite difficult to detect within a weed culture. The latter arise when temperatures are high and the humidity in the air is quite low. Outside, the lack of water associated with high heat represents conditions favorable to their arrival. Cochets feed on plant sap, which will gradually weaken the latter.

They are mobile on the entirety of the plant structure, they leave sticky traces as a signature of their passage. It is important to know that the secretions of this malicious insect are able to develop a fungal disease known as fumagine.

So you might see 2 problems appear in 1, so it is logically better to avoid its presence. Another aspect of capital importance is that the latter are difficult to eliminate through a treatment composed of insecticide products, even those which are chemical.


The nematodes are small verses with a slightly elongated round shape, of which there are more 25,000 species listed to date. Nematodes measure 2.5 mm on average, this is the reason why they are difficult to see with the naked eye. You should know that half of them are pests for plants or animals. Certain species of nematodes are beneficial, but unfortunately many of them significantly affect the cannabis plant.

Nematodes feed on vegetable cells, bacteria, mushrooms and microorganisms that litter the ground. The most formidable nematodes for marijuana plants are those that Intensely affect the roots.

The harmful effects are quickly felt, because we are witnessing the sudden slowdown in growth or flowering, because we can observe progressive chlorosis in the leaves and if the infestation evolves at a higher stage, it is possible to assist to the swelling or atrophication of the roots, which will then have a more rough aspect.

The unfortunate result of this action is the slow and programmed death of plants from Premium seeds, which wear your interior or outdoor garden. Many cultivators could think of the beginning of the infestation that they are in the presence of different nutrient deficiencies, but in fact the real cause of these problems are indeed the nematodes. 

The best prevention measures to be applied to limit the appearance of insects on the cannabis plant?

  • Maintain air temperatures as a stable humidity rate, and adapted to each cycle phase
  • Make sure the space is well ventilated, with also a renewal of the air adapted to its dimension
  • Clean the culture space as much as possible, especially without allowing plant waste dragged
  • Make watering in just quantity of water and nutrients, with also a PH and a well -adjusted EC
  • Apply a wide spectrum preventive treatment against insects and fungi in half and at the end of growth
  • Disinfect your space to the bottom using detergents or insecticides/fungicides with broad spectrum between each cycle
  • Never reuse land or a used substrate when restarting a new culture cycle from Seeds

Optimal solutions to eliminate harmful insects from cannabis 

Red spiders

To treat such a scourge, you can use a treatment from neem oil, black soap or of pyrethre oil. We do not recommend the use of an insecticide based on chemicals, because we have realized over time, that the latter have become resistant to many chemical molecules present on the market these days.

The cultivators used them too automatically, which caused genetic mutations promoting their resistance to this type of treatment. However, we strongly recommend the use of natural predators such as mites "Phytoseiulus persimilis" for a severe attack, or "Amblyseius californicus" in prevention system. They are really very effective, to do this, it is necessary to integrate and maintain a quantitatively large population throughout the duration of the cycle.

The miner fly

You can have adhesive strips to catch the maximum of these, especially adults, because in this way they will not be able to place their eggs on the different parts of the most beautiful plants which come from the greatest quality seeds.

Do not hesitate to eliminate larvae in formation in the tissues of the leaves manually using your nails or a pointed device, this will avoid additional ravages. Otherwise, you will have no other solutions than to apply is a treatment using a natural insecticide like spinosad Or, if the infestation is too large, based on chemical insecticides as a last resort. 

The white fly (aurode)

To get rid of it, you can use yellow -colored adhesive strips, or apply a spraying based on a Neem oil solution or black soap Every 5 to 6 days approximately, until the complete disappearance of these critters. Natural predators like The bee "Encoursia Formosa" or a kind of bug like "Macrolophus Caliginosus", will also do a great job.

The ants

Just apply the cinnamon On the affected parts, and the latter will die quickly, it is radical and natural!


We advise you to integrate a natural predator like chrysop, because they eat them, or even ladybugs, of the parasitoid wasps or the fungus "Verticillium Lecanii", who will literally kill them.


We recommend putting a population of Biological predators "of Amblyseius Swirskii" Or "D'Amblyseius cucumeris" On your magnificent plants from Seeds.

The caterpillars

You can eliminate this phenomenon thanks to the use of a natural insecticide, which is none other than Infusion of pepper and garlic, or by freeing "Trichogram" wasps, "Podisus Maculiventris" In the heart of space. The use of the fungus "Bacillus thuringiensis" is also formidable against the latter.


To overcome these, we advise to apply a spray of a Alcohol and soap solution. For the preparation, mix a teaspoon of liquid soap in a little lukewarm water, add 1 liter of water, with also a teaspoon of alcohol to be burned in addition, mix again effectively and voila .


You can spread a bacterial substance like "Pasteuria Penetrans", which stops the growth of their population in a fairly short time, because the latter decimate their population at an early stage of their training. The resolution of this problem can also be envisaged thanks to fungal individuals such as "Arthrobotrys oligospora", "Entomophthora gypsophile", or the variants belonging to the genre "Verticillium", which are of formidable efficiency.