+34937250967 9:30h - 18:00h GMT+1
  • es
  • en
  • fr

In this article we are going to talk about plagues that affect our cannabis plants during warmer months of the year. We will also look at how to avoid their emergence or, at least, slow them down as much as possible.

The plagues that we will talk about are: The Red Spider Mite, Mites and those which are called Microscopic mites. Don’t miss this post if you want to learn how to fight against these plagues in a biological way, as well as how to fight them with the use of phytosanitary products (chemicals), keeping in mind, above all, the safety conditions at the time of application of each of these products.

Finally, we will look at a few different recommendations for the use of these types of products.


Red Spider Mite (Tetranychus urticae)


The Red Spider Mite is the most feared plague for indoor growers in the warmest months of the year. It is a tiny insect from the mite family, in which you can find infinite names for different types of mites. The Red Spider Mite measures around 1mm and because of this, it is easier to see using a pocket magnifying glass.

This plague feeds on the plants and it tends to be found on the underside of the leaves when it first appears, producing small bites underneath the leaves.

As time passes, if you still haven’t been able to get rid of it, you’ll see how it weaves spiderwebs on the outside of the plant, making it hard for the plant to perspire properly and causing irreparable damage that may include: reducing the effectiveness of photosynthesis, the plant’s perspiration and reducing natural growth.

The best way to avoid the emergence of the Red Spider Mite Is to maintain a clean grow area and to disinfect each that time you begin a new crop cycle. By doing this you avoid giving allowing the mite’s eggs to lay dormant and hatch in the future. It is very important to remember that this plague lays eggs in the dirt, where they can also survive the winter. Given this, the soil from an infected plant should never be reused.


Araña roja en planta de marihuana


How do you eliminate the red spider mite from marijuana plants?


  • In order to fight this plague you can employ the use of biological remedies that can be found in a Grow Shop or use natural predators (Phytoseiulus persimilis, Amblyseius californicus, stethorus) in order to control or fight the red spider mite.
  • Within phytosanitary products specifically designed to fight against the Red Spider Mite we can find Abamectin and Milbectin, which are two chemical products that should only be used in the growing phase or in the first week of flowering. You should never use these products when the flowers are maturing, since you run the risk of leaving traces of these products in them.

Remember that each plague has its own growing time, meaning that we should repeat the fumigation several times, in order to avoid reappearance.


Mites and Microscopic Mites


When we talk about mites and microscopic mites we are talking about arachnids that measure around 1mm in the case of mites and 0.2mm in the case of microscopic mites. These insects bite the soft parts of our plants, weakening them to the point in which the vital rhythm of the plants is slowed.

Due to the rapid growth of this plague, you need to act quickly just as you would in the previous case, otherwise you can’t expect the flowering phase to end the way that it should.


How can we eliminate mites and microscopic mites from our marijuana plants?


  • In order to fight against this mite in a biological way we can use a mixture of potassium soap and horticulture oil. This mixture can be fumigated over the whole plant, especially on the underside of the leaves, where we can find the majority of these insects living.
  • In order to fight this plague with phytosanitary products, we can continue using Abamectin and Milbectin, and in the event that the plague persists we can alternate the use of both products.

As in the prior case, cleaning the grow zone and tools that we use will be of great importance in the event that we are suffering from this plague, since it can reappear at another time causing the same damage to our crop.


Advice for the use of biological insecticides


  • Even with biological products the use of gloves and a mask is still advisable.
  • Making the mixture with chlorine free water can be an advantage, since you can be sure that you aren’t interfering with the effectiveness of the product.
  • As with the preparation of chemical insecticides, adjust the measurements of the preparation for necessary use at each moment. This will make it such that we are taking 100% advantage of the product.


Advice for the use of phytosanitary products

  • You should use adequate gloves and mask based on the product that you are using. Never prepare the mixture without using gloves since this can be dangerous. The use of a mask is recommended during fumigation of your cannabis plants.
  • It is better to prepare the product mixture in small quantities, since if you prepare too much, you will have to throw it out, causing damage to the ecosystem and wasting the product.
  • I never apply phytosanitary products when the plants are in the flowering phase, since you can’t find this safety condition specified by any manufacturer. In the case of the use of these products in the flowering phase, we should keep in mind the longest safety terms that the manufacturer of the product recommends.


Thank you to all our readers for another week.




«Tetranychus-urticae» de J. Holopainen – From my camera. Disponible bajo la licencia GFDL vía Wikimedia Commons – https://commons.wikimedia.org/wiki/File:Tetranychus-urticae.jpg#/media/File:Tetranychus-urticae.jpg