How To Get Rid Of Whiteflies On Marijuana

How To Get Rid Of Whiteflies On Marijuana

Probably all or most marijuana growers have an infestation of whitefly at some time or another, those tiny whitish mosquitoes that can leave our plants sick or eradicate them. Indoor crops can be very susceptible, and infestations can quickly reach critical numbers due to the perfect conditions and no natural predators.

Treating our plants to eliminate this pest is essential if we get good results at the end of the harvest, but as always, the best way to avoid it is to prevent it. Below we will explain everything about this bug since knowing the enemy will make it easier to dispose of. Likewise, we give the best solutions and methodologies for use.

How To Get Rid Of Whiteflies On Marijuana
How To Get Rid Of Whiteflies On Marijuana

What are whitefly?

It is a flying insect that lives and reproduces in warm climates with temperatures above 15 degrees Celsius and 35 degrees Celsius Temperatures below or above these parameters, and the whitefly cannot survive. There are dozens of varieties of white fly, but the most common in the cultivation of marijuana is the species Trialeurodes vaporiorum. Its size is tiny, between one and two millimeters, and its color is whitish or yellowish.

Indoor grow rooms where the temperature is usually optimal for these insects mean they can multiply their population x 200 every month. Since the females lay an average of between 180 and 200 eggs, they can quickly become an overly abundant and damaging pest for our plants.

Eggs are laid on the undersides of the leaves of the marijuana plant and are where they mature until hatching. The egg size is tiny, just 0.25 millimeters, so unless you have a widespread population … it can be challenging to see these eggs without the help of a lens or microscope.

What are whitefly?

How does whitefly affect your Marijuana plant?

This insect is very harmful to our plants as it feeds on plant sap. Having a couple of white flies is not a problem, but it is likely that once you have seen the eggs, a couple will soon turn into hundreds.

Imagine thousands of insects sucking sap from a cannabis plant; the plant’s future if the pest is not removed is very likely death. If the plant does not die, the buds’ production and quality will be much lower. If the plant is in veg, it will be seriously affected, losing vigor and even stopping growth entirely.

Furthermore, these insects can transmit different kinds of viruses to our plants, which are weakened by the removal of sap by the whitefly …. will be very severely affected.

How whitefly affects your Marijuana plant?

How to detect whitefly on marijuana plants?

How to tell if we have whitefly in our growth or not it’s straightforward. Whiteflies feed on our plants’ sap; when this happens, small circles occur in the leaves of a lighter color. It is plain to see that we have some insects on our plants.

When we see that leaves of our plant have this kind of discoloration or pitting, we must look at the underside (bottom) of the leaves to find the source. If we see these small flies or their eggs, we know that it is a plague of whiteflies.

If the pest is already widespread in our growth,  shake a little leaf and see dozens of small white or yellowish flies fly out. Luckily they are easy to identify without using microscopes or lenses.

How to detect whitefly on Marijuana plants?

Preventing whitefly in crops of marijuana

The best medicine for all diseases and pests is always prevention. Insects such as those most often interested in our cannabis plants are also susceptible to certain plants in nature, some of whose odor is repelling or are toxic to these insects.

Neem oil is one of the best repellents, is entirely natural (100% BIO), and is economical. It is enough to spray our plants with water and a little diluted neem oil every fifteen or twenty days to keep whitefly and many other insects away from our crops.

In indoor growing, we can also make a filter in our grow room’s air inlet, thus preventing insects’ entry. For instance, stockings can make an excellent filter, letting the air pass while preventing certain insects from sneaking.

Preventing whitefly in crops of marijuana

How To Get Rid Of Whiteflies On Marijuana

Eliminating whitefly infestation on my cannabis plants

If we already have an infestation on our plants, we must act immediately. Since they reproduce exponentially and in just one month could multiply their population by two hundred. We can use two options: remove the whitefly with natural products (biological) or chemicals.

If we are in the flowering stage, chemicals should no longer be considered an option, as they may damage the buds or leave traces of toxins in them.

Eliminating whitefly infestation on my cannabis plants

Remove the whitefly with natural options:

Mix potassium soap (or soap) in a bucket of water and add neem oil. With the help of a sponge, we can wash all the leaves individually on our plant, careful not to break the stem and wipe both the top and the bottom of the leaf. Repeat this every ten days.

Use a yellow adhesive anti-mosquito trap near our marijuana plants infected by whitefly. The whitefly is attracted to this color and remains stuck on the web.

Use a natural pyrethrin-based insecticide (chrysanthemum extract) and spray our plant every ten days.

Chemical options to kill whitefly:

We must NEVER use chemicals if our plant is in the process of flowering because toxins could stay in the buds that we later smoke or eat. Go to a nursery or grow shop to buy the chemicals used on food crops. NEVER use chemical solutions in our plant if in Flower. Spray our plant with products purchased and follow the instructions. Don’t be tempted to mix a concentrated solution as this could kill your plants and the pests! Use in conjunction with the yellow anti-mosquito traps we mentioned earlier.Chemical options to kill whitefly

If you have any questions or suggestions, you can leave a comment, and we will help you solve them.


  1. They thrive on CO2 when the ppm is in the 1200-1500 range, I would have thought 100% CO2 would kill your plants pretty quickly high doses would internally affect the PH of your plant (making it acidic)

    I wouldn’t recommend it but if in the interest of science you want to try it and report back I for one would be interested ; )


  2. Since plants thrive on CO2, would a 100% CO2 environment really hurt the plants? I may have to regulate the inside temperature (keep in shade, water down can maybe). I may also have to leave a small opening with the lid for gases to escape (and maybe a few lucky white flies).

  3. Hello Quete
    I think you might suffocate the plants instead!. Seriously you would be better spraying the plants just before the dark period with a dilute soap solution or neem spray. Both are very effective at killing whitefly.

    good luck


  4. I have small, 2-3 foot plants and am considering placing the flowering plants inside a lidded trash can with a CO2 generator and hopefully suffocate the bugs within the 6 hour dark period.
    Any comments on this idea?

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