Stop! Invasion of the Spider Mites

Stop! Invasion of the Spider Mites

Every grower's nightmare, and sometimes a big problem emanates from the Red Spider Mite - a common sap-feeding mite that can cause mottled leaves and early leaf loss on a wide range of greenhouse and garden plants. It is also known as two-spotted spider mite - are hard to see, as they're only about the size of a grain of pepper. Still, for their size, they can really wallop your plants. If leaves of your plants look yellowed and have tiny webbing between them, you might have spider mites.

They are not insects but rather arachnids, which means they're in the spider family. Spider mites attack trees and garden plants, making the leaves look stippled, yellow, and weak.
 Spider mites can be an especially tricky pest in the indoor environment since they are so small they can build up a big infestation before a grower even notices a single mite. Many growers see the distinctive tiny spots of a spider mite infestation and think it's some sort of nutrient deficiency, not realising it's actually something far more sinister.

Spider mites are despised by growers. Here's why...

  • Rapid reproduction - a single mature spider mite can produce a million mites in less than a month
  • Disappearing act - spider mites often appear to be gone/killed, then they come back with a vengeance days or weeks later, right when you thought you'd gotten rid of them for good.
  • Big appetites - spider mites can eat up your tender plants in an amazingly short amount of time; a bad infestation has been known to kill plants overnight
  • Webbing - spider mites cover leaves and buds with a fine mesh of silk webbing, ruining whole crops even after you get rid of the spider mites
  • Zombie-like resistance - spider mites quickly become immune to whatever you do to try to kill them; if you don't take care of your spider mite problem by eradicating them completely from your grow room, you may soon find you have a population of 'Super-mites'. The two-spotted spider mite which specialises in cannabis seems to be particularly resistant to insecticides, and is sometimes referred to as "The Borg" with two spots on their back can be almost impossible to eradicate.

Prevention and Maintenance

Many indoor growers get spider mites from bringing in cannabis clones that are infected, or from visiting another grower or grow room with spider mites. Even just a few eggs on a clone or a few spider mites on your clothes is all it takes to start a full fledged infestation. This is the most common way people get spider mites, especially the marijuana-specialist spider mites ("the borg") which can be almost impossible to kill!

Most importantly, never move plants or clones from the outside world into your grow room without treating and quarantining them. If you get a new plant, keep that plant away from your other plants until you know that it's clean. 
Make Sure You Have Them

Since spider mites are so small, you have to make sure that they're the culprits for your plant problems. Hold a sheet of white paper under an unhealthy branch. Hit the branch and see what comes out. If tiny red, yellow, green, brown, red, or black specs fall on your paper and begin to crawl around, you have spider mites. 

Hose Them Down

Spider Mites like dry, dusty conditions. Spray your plants' leaves or needles with water. Hose down garden walkways and other dry, dusty spots. That will make them unhappy. 

Clean Up! 

Having debris around trees and plants make spider mites feel welcome. Spider mites do better in some environments than others. Luckily the conditions that make your plants happy are not that great for spider mites. So if you're taking care of your plant's environment, you're also helping to prevent bugs and mould.

  • Make sure you have great airflow in your room because spider mites thrive in stagnant air. Creating lots of air movement will not only help prevent spider mites, fungus gnats and mould, but your plants love it too!
  • Spider mites like hot, dry weather. Maintaining a comfortable room temperature and a moderate amount of humidity in the grow room will help prevent or slow down a spider mite infestation.
  • If you have an air intake from outside, make sure you have some sort of filter to keep bugs from getting in
  • Sprinkle Diatomaceous Earth on top of your soil and all around your grow room - this all-natural remedy is safe for humans (we can even eat it), and works because it is very jagged on the microscopic level. Tiny spider mites get ripped apart by diatomaceous earth while plants grow through it happily

Keep a close watch on your plants, and react quickly at the FIRST site of spider mites!!!!

There are a number of natural products and methods that can be used, on the plants that are effected by spider mites;

Method 1 - Neem Treatment

  1. 7ml of Virgin Neem Oil per Litre of warm water, at about 24 degress - adding 3 Droplets of Ecover Lemon and Aloe Vera Washing Liquid.
  2. Once you have added the warm water, to the sprayer add the droplets of washing liquid and the 7ml of virgin neem oil per litre of warm water, please not that the mix work better with warm water than cold. 
  3. Now place lid on the sprayer, and shake; you will notice that the mix starts to foam a little.
  4. Seal lid on the sprayer tight, and now as you spray the effected plant also agitate the sprayer so that the mixture in the spray chamber stay nice and well mixed.

Method 2 - Chemical treatment

  1. Syngenta Dynamec is a chemical treatment to kill Spider mite. 
  2. Adding 1ml to 2ml of Dynamec per litre of warm water mixed in a high pressure sprayer.
  3. Syngenta Dynamec is made to kill and control spider mites and western flower thrip. It may be used in protected and out door flower crops, and protect Tomatoes and cucumbers crops.
  4. It is necessary to where the correct PPE clothing and apparatus.
  5. Syngenta Dynamec contains 18g/ltr Abamectin with (1.84% w/w) with Cyclohexanol.

Method 3

Alternating between both methods one and two, every couple of days, will eventually kill the Spider Mites. As stated earlier a female mite can reproduce like no other pest, and cause serious damage to you crop.

Growers often wonder what they are doing wrong, Firstly remove all dead material and super infected leaf material. Clean area top to bottom, Don't be lazy, because Spider Mites are productive little buggers finding any way to repopulate the plant.

Spray the top of the soil or medium that you are growing with. spray the undersides of the all the leafs and top side of the leaf as well, spray the stem.

Repeat, Repeat and Repeat Again...

After the plant recovers and there is no sign of the Spider mite, go through the plants and again remove any leafs that looked effected. Check all old growth, and keep a good eye on fresh growing shoots. After the first treatment you mite think, my plants dead, Cannabis is a hard plant. Never give up, or give in. Spray them, Spray them, Kill them.

A good grower, will always use his eye, Don't leave anything to chance. There are a number of other product that can be used to aid the disruption of mite production and ultimately death.