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By Steven Voser

Whiteflies are a common garden pest that have the potential to wreak havoc on your cannabis grow.

In this article, we look at whiteflies, what they are, how to get rid of them, and how to protect your grow against future infestations.

For more articles like this, grow tips and much more, remember to bookmark our blog. Also make sure to check out our earlier post for more tips on cannabis pest prevention.


Whitefly is a common garden pest that affects a variety of plants, including Cannabis. They behave very similarly to spider mites and are usually found on the underside of leaves where they steal essential nutrients from the plant.

Whiteflies look like tiny white moths with yellow bodies and are roughly 2 millimeters long. Adult flies are usually found on the top parts of plants while nymphs are usually found lower down.

Whiteflies usually lay eggs on the undersides of leaves. Eggs are usually greyish or yellow and feature a cone-like shape. Adult whiteflies can lay up to 400 eggs, which usually hatch within a week.

Eggs hatch into flattened nymphs (often called crawlers) which feed on the plant for about a month before developing into adult whiteflies. Adult flies usually live for roughly 4 weeks.

Whiteflies pest cannabis


Whiteflies are relatively easy to spot. Adult flies are usually found flying around the plant or are grouped on the underside of leaves. Shaking a plant will cause the adult flies to fly away, making them easier to see.

Eggs are normally deposited in circular groups of roughly 30-40 and can be found on the undersides of leaves.

When feeding, whitefly punctures the leaves of the plants in order to suck nutrients from them. This leaves white spots on the top side of leaves, which is yet another clear sign that you’re plant is infected, even if you can’t directly spot any flies on your plant. Large populations may cause leaves to become yellow or die off completely.

Whiteflies usually consume more plant nutrients than they can digest. They excrete these excess nutrients as a sweet, sticky substance known as honeydew. If your plants are infested with whitefly, keep an eye out for honeydew on the leaves of your plants as it acts as a growth medium for a black, sooty mould that can hinder a plant’s ability to photosynthesize.

Honeydew also attracts ants, which can further interfere with the presence of other natural whitefly predators, potentially worsening the situation in your grow room.


As with any pest, it is always best to take preventative measures against whitefly to begin with. It is always harder to get rid of a pest than prevent one, and whiteflies can be particularly tricky to manage in large populations (which don’t take long to form).

Like when dealing with spider mites, we suggest you address any environmental factors that might be causing your infestation first, then follow up by hosing down and pruning your plants.

Whitefly lifecycle
As always, we suggest you stay away from any chemical pesticides since they may kill off other insects that naturally prey on whitefly. Plus, most garden pests are good at building up resistance to pesticides, which may make matters worse in the future.


Whiteflies like warm weather and thrive in conditions where there are no (or few) predators around to prey on them. Therefore, it’s important to make sure that your grow room is free of dust and any other insects that might naturally interfere with whitefly predators (such as ants).

Also, make sure your grow room temperatures aren’t too high (between 20 and 25ºC or 68 and 77ºF is ideal).

If you’ve noticed some whiteflies in your grow room, you may want to bring temperatures down a little to fend off a bigger infestation (try to bring them down past 20ºC or 68ºF but be careful not to damage your plants).

Finally, make sure your grow room is well ventilated, an important step in fending off most garden pests.


Once you've addressed the environmental factors that might be contributing to your whitefly problem, it’s time to prune any infected leaves. Make sure to discard any prunings immediately to avoid infecting other plants.

You may want to try hosing down your plants. However, whitefly eggs are notoriously hard to remove from plants and might require a decent bit of water pressure which could damage your plants.

Next, we recommend you use some of the following techniques for removing whiteflies.



Ladybugs, lacewings and predatory mites prey on whiteflies and their eggs. If you haven’t already, we highly suggest introducing these insects into your grow environment as they’ll help you control a wide variety of pests (including spider mites).

We recommend starting with ladybugs. For more information on how to use ladybugs in your cannabis garden, click here.


If you’re not able to prevent or control a whitefly infestation using the above methods, you may want to try some of the following organic insecticides:

Oil cannabis whitefly pest organic insecticides

  • Essentria IC3: This product contains a generous mix of horticultural oils and can be directly applied to your plants without damaging them. Remember to apply it liberally with a mister, and to use it daily as it only remains active for roughly 8-12 hours.
  • Spinosad: All Spinosad products are completely organic We suggest spraying plants directly to kill any flies upon contact as well as adding some during water to help fend off whiteflies and other pests in the future.
  • Insecticidal soaps: These are great for spot-treating infected areas of your plants. Try not to get them directly on any buds and consider using them multiple times to ensure you’ve killed off all flies in your grow area.


Essential and horticultural oils are becoming increasingly popular as a way to control and prevent pests. Neem oil is arguably one of the most common essential oils used on cannabis and other plants, but there are others which are also rumoured to do the trick.

Besides neem oil, you may want to try eucalyptus, rosemary, lemon, and cinnamon oils. Simply mix them with water and apply them to your plants with a mister. Try not to get any directly on your buds as they may alter their aroma profiles.

Alternatively, you may want to treat your plants periodically with horticultural oils. We generally recommend using vegetable oils, such as canola, soybean, or cottonseed. These are usually less likely to alter the smell of your buds.

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