Early Signs of Spider Mites and How to Get Rid of Them

 The spider mite is one of the most common pests in plant production. This mite feeds on the sap of more than 200 species of cultivated plants and weeds. Thus, it settles everywhere, as much in the interior productions as the exterior. Very small, it hibernates in cracks (trunks of trees and shrubs, on the ground, crop residues, door seals, etc.). It travels with the wind, on clothing, through cuttings, or contaminated soil. The first symptoms of their presence can be difficult to detect, and under certain conditions, infestations explode quickly. 


What are spider mites?

Spider mites can infest a grow room without even being noticed by the naked eye! These tiny pests measure between 0.4 and 0.5 mm, leaving behind small white, orange or yellow spots on the leaves by piercing their cells and sucking their contents. There is a tendency to confuse these spots with nutrient deficiencies. If not acted upon immediately, it will result in a complete infestation where whole leaves will turn yellow and fine webs will gradually appear on the flowers. They are often found on the backs of cannabis leaves, where they lay their eggs. They can reproduce millions of times in just one month. They quickly become immune to anything that tries to kill them. If they haven't been discovered yet, they will turn into "super spider mites": two-spotted spider mites that are ultra-resistant to insecticides and almost intolerable. 

The life cycle of spider mites

It is important to understand its life cycle to detect the spider mite properly and act quickly to control populations. This pest can grow very quickly; it varies with temperature, humidity, and the host plant. For example, it takes 36 days at 15 ° C, ten days at 25 ° C or six days at 35 ° C to complete a complete "egg to egg" cycle. At 25 ° C, a female can lay up to 170 eggs, which gives a good idea of how quickly irreversible damage can occur. The fertilized females, red-orange in color, hide and enter diapause to survive the winter from August. Both the eggs and the adults then go into "overwintering" mode. 

Early Signs of Spider Mites

Spider mites can be a tricky pest to control because they are so small and hard to see. You may not notice them until it is too late, but early signs of spider mites include yellowed leaves on plants or an increased presence of webbing. Spider mites are arachnids that feed on the sap in plants by piercing their cell walls with needle-like mouthparts. They will also create webs to catch prey like eggs, larvae, and other insects for food.

The problem is, these pests love to devour whole plants for a brief period and then cover them with webs. They are very good at disappearing and coming back a few days or weeks later, determined to take revenge. They are tough to get rid of, so it is vital to take charge of the situation as soon as you notice them. The first step in purging your crops of these spider mites is to accept that you have an infestation. Indoor growers need to be even more vigilant when inspecting their plants for pests and diseases. Spider mites may, at first glance, appear as small black spots, but when they attack, you should be able to see small spots of color on the leaves. At this point, the leaves will likely turn yellow, and this will kill them prematurely. They also can completely cover a crop with a fine silk web that quickly catches dirt and dust. Always check both sides of your leaves at regular intervals. If you've ever experienced a spider mite infestation, you should treat your grow space, as these might just be hiding and reproducing before planning their next attack. There are different spider mites, but they can only be detected by the marks that appear on your plants, such as eggs, small animals, webs, or yellow or brown spots found on the leaves. 


Spider mites are usually found below leaves, where they pierce plant cells to feed on them. When present, small discolored dots appear and are visible on both surfaces of an infected leaf. Over time, the foliage turns yellow, dries up, and falls off.

When the spider mite population proliferates on a plant, it weaves very thin "cobwebs" on the damaged foliage. It is called a hotbed of infestation. They quickly colonize the plants on the periphery. When the infested plant becomes less vigorous, the spider mites will begin to migrate to other plants. They gather at the top, weaving tiny connecting threads between the plants or carrying themselves away by the ventilation. 

How To Get Rid Of Spider Mites When You Notice The Early Signs?

If you suspect spider mite infestation, there are ways you can identify these tiny pests and get rid of them before they do any more damage.

Adjust your settings

Spider mites love warm temperatures and low humidity. In addition, they are very attracted to plants stressed by too much ventilation, irrigation problems (e.g., clogged nozzle), fertilization, pH, diseases, and others. Therefore, before starting a biological control program, it is essential to adjust your production conditions not to favor these pests. To do this, opt for a temperature of 20 to 27 Celsius and perfect leaf humidity (~ 60% and more). 

Clean your production area

Spider mites are very small and can easily hide in growing media, cracks, and other structures within the production area. To reduce the risk of contamination, clean the production part with a mixture of soapy water and bleach between each cycle. In addition, take care to always sterilize, after each use, the surfaces of tables, tools, and other objects present with a mixture of isopropyl alcohol or hydrogen peroxide. 

Soak the foliage

Spider mites can infect a healthy room through the arrival or transfer of toxic plants. Soaking is a technique that reduces this risk. To do this, on arrival or before the transfer, completely soak the plant's foliage (stem and leaves) in a mixture of water and natural oil or soap. Note that the foliage of some plants may be sensitive to these products. Always check with your sanitary product supplier before practicing this method. 

Introduiser des prédateurs naturels

Ladybugs and predatory insects can control and reduce the spider mite population but not eradicate them. However, it is a good alternative if you are close to harvest and do not administer any chemicals. 


It's essential to keep a close eye on your plants and their soil. If you see any signs of spider mites, it is time to take action immediately before the problem gets out of hand. These pests can be hard to detect and remove and will destroy the plant's leaves and flowers if they aren't taken care of quickly. 

Spider mite infestations can happen to indoor and outdoor plants, so never assume that this won't occur because you have an inside garden! It is important to act fast when dealing with these pests before they do too much damage to your precious flora. Know what signs to look for to take action against them.

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