Cannabis pests- Aphids

In this article:


Recognizing Aphids

Aphids are very small insects and often seen on cannabis plants. They are found everywhere in the world. The thing about aphids is that they come in many different sizes and shapes. The appereance of a Aphid changes throughout its life so they look very different when they are young, compared to adults. Next to that, they come an multiple colours which makes it even more hard to recognize them. They can be green, yellow, red white, brown and black.

Black aphids attacking a plant
Younger aphids often appear red and gets mistaken for a different insect. (Most aphids on cannabis plants are green/black)

Aphids love cannabis plants because they pierce the plant tissue with their mouth and suck the juices out of it. They are never alone and their colonies can be found hidden underneath stemps or leaves. After a while, your plant will turn yellow and show other signs of stress. However this is not the only problem with Aphids…

Sometimes Aphids are winged and people mistake them for flies or other insects. However the shape of their body is always the same. These are alse called: Colonizers
White Aphids infestation on a cannbis plant

Honeydew and Black sooty mold

The problem with aphids is that they produce massive amounts of a substance called “honeydew”. The bad thing about hese sweet honeydew drops is that they attract a fungus called “sooty mold”. This type of mold will begin it’s growth on the honeydew, but slowly expands to the leaves and stems of your plant turning them black. This will obstruct multiple processes in the plant and once it reaches your buds, it will make them un-smokeable.

Aphids producing honeydew
A black Aphid colony is quickly taking over a cannabis plant. Aphids will never be alone and their colonies can be found under leaves and stems

Cause of an Aphid infestation

An Aphid infestation is pretty hard to avoid. Especially when growing outdoor, there is a great chance your plant will be the new home of a colony of aphids. An infestation starts with the winged aphid landing on your plants and laying eggs. So don’t think a winged aphid, not eating your plant is friendly as they can start a new conoly pretty quick.

These winged Aphids are often referred to as flies or a “greenfly/blackfly bug” (depending on it’s colour). People oftens mistake them for flies because of their wings but if you look good, you will see that the shape of their bodies are identical to regular Aphids.

Black winged Aphid, often referred to as “black Fly” or “Blackfly bug”

It’squite hard to avoid a Aphid infestation, especially outdoor grows are easily accesable for Aphids. Just a few winged Aphids visiting your plant can cause a nasty infestation. The Eggs they lay hatch quicky and the first young aphids (nymphs) will start eating the leaves. They can be recognized as small white specs (Or other colours). Nymphs will mature in 7-10 days and while growing, they shed their skin a few times. These exoskeletons will be left on your plant and could end up in your dried nugs.

Young aphids (Also called: Nymphs) and bigger ones underneath a cannabis leave. The begin of an infestation.

Once a generation grows up and become adult, they are quickly ready to give birth and start a new generation. Most of these adults are female and able to produce many new Aphids. Because they grow up so quickly and give birth to many babies, it just takes a few generations (weeks) that a few winged colonizers take over a plant with thousands of Aphids.

A unique thing about Aphids is that when colonizing a plant, new borns are mostly born without wings. Only once the plant become so stressed (or too crowded) that it can’t support the hunger off all Aphids, they will start producing winged colonizers. These winged Aphids will look for anew victim where they start the proces all over again!

How to treat an Aphid infestation

Now we know that Aphids can reproduce very quickly, the first step is to act quickly once you spot them. Aphids can hide pretty well so make sure you examine your pants very good multiple times a week (under leaves and between buds/stems). Especially when growing outdoors, it’s hard to predict when a winged colonizer visits your plant. Examining your plant applies for all kind of bugs, not only Aphids!

There are a few methods to treat an Aphid infestation:

1- Removing them by hand   

The first and most easy method is removing the Aphids by hand. Depending on the stage of your plant, you are able to cut off infested leaves and stems. This Should be done in the final weeks before harvest. Not recommended in vegetatieve phase. Another option is spraying them of with a water hose and some pressure (watch out for damage to the plant).

2- Using a natural enemy

There or multiple enemies of the Aphid that can be used to fight them in a natural way. Think about: Lacewings and ladybugs/beetles. These insects are not harmfull for a plant and love to eat lot’s of Aphids. Ladybugs are available on the internet or better gardening stores and can be placed manually. Despite this, they fly away in a day or two (especially outdoor) and leave some Aphids that will reproduce again quickly. One option is placing your plants in quarantine (for example: grow tent) with the ladybugs for a few days.

Ladybug hunting on some Aphids. They love to eat huge amounts of them!

Remember: Never use chemicals or insecticides that are harmfull or toxic for humans. Make sure the product is organic and good for human consumption!


3- Insecticidal soaps

An often used product for Aphids is Insecticidal soap. This special spray is safe and weakens the outer shell of an Aphid, eventually drying them out. These soaps won’t leavy any residue on the plant and wash off easily. Thats why you need to make sure to apply it properly and multiple times on the plant (always avoid the buds, even when it’s safe).


4- Spinosad products

Spinosad is an 100% natural and organic pesticide that will effect the Ahpids nervous system and eventually kills it. Only contact or ingestation with Spinosad is enough for an Aphid to die. You should spray this product all over the plant and anywhere you see the Aphids (especially under the leaves). Spinosad products often only work for 24 hours, so respraying the plant is necessary.
Spinosad is made from a special fermentation of soil bacteria called: actinomycete Saccharopolyspora spinosa. This organic product might not work as aggresive as other pesticides but is still very effective for Aphids and extremely safe for humans, pets and plants. Another great thing for outdoor/organic growers is that this product is specifically harmfull for Aphids and less for other insects. So you can combine this spray with ladybugs.

Our recommendation: Montery garden insect spray!