How to Deal with Aphids on Cannabis Plants

Aphids close up
October 01, 2020

Aphids on marijuana plants are quite common but are nonetheless a big problem. Truth be told, they are not the only destructive pests. But they are among the most frequently occurring. Spotting them timely and reacting accordingly is essential to preventing an uncontrolled infestation. There is no 100% guarantee that you can prevent aphids on pot plants to begin with, but you sure can eliminate them once they appear.

What Are Aphids?

Aphids are small, winged insects that proliferate and live on the underside of leaves. They have an oval body, between 1-3mm in size. Usually, they are green, yellow, or mottled but could also be black, brown, or red. Although they are small, spotting aphids on cannabis plants is not that difficult as these insects live in large groups.

In a small number, the damage caused by aphids on marijuana is not significant. Aphids pierce through the leaves and feed on the sap. On the other hand, a colony of aphids on cannabis plants can cause mass destruction by feeding on and sapping away important nutrients, causing the leaves to turn yellow, wilt, and fall off. Consequently, affected plants experience stunted growth.

Besides depriving your plants of precious sustenance, aphids on pot plants also pose another threat. One or more could be carriers and introduce harmful pathogens – bacterias, viruses, or fungi – into the plants. This pest also excretes concentrated sugars called honeydew, in which sooty fungus might grow and cause necrosis of the leaves.

Trivia: Ants love honeydew, and they will protect aphids from predatory insects to ensure a constant supply.

An extensive proliferation poses a threat to future plants, too. They can pierce stems to seek refuge and lay eggs – lots of them. During the cold winter months, those eggs lay dormant, waiting for the warm, humid climate to hatch and wreak havoc once again. If this happens you may end up with an unmanageable amount of aphids on cannabis plants that are already highly weakened by the colder temperatures.

Signs of an Infestation of Aphids on cannabis plants

There are plenty of visual cues that might indicate the presence of aphids on marijuana, other than spotting them, usually on the leaves’ underside. For example, you may see the white exoskeletons of dead aphids.

Leaves turning black may indicate the presence of sooty molds. Discoloration, curling, and wilting can be a sign, too – although these conditions could be due to a plethora of other reasons.

Aphids thrive in the same temperature range that is most conducive to marijuana growth – around 65°C to 80°C. The conventional thinking is that they are more likely to proliferate indoors, where the temperature is constant.

But these insects can also proliferate outdoors. Be observant and take notice of dead aphids. They appear off-colored, bloated, flattened, or moldy. You might even notice the presence of predatory insects such as lady beetles and lacewings.

Ants will protect aphids from their natural predators. They do this so that the aphids could leave one of their favorite foods – honeydew. Some species of ants may also carry aphids to other plants – a fresh “grazing area.” If you see ants, then that might be another indicator.

Eliminating Aphids from Marijuana Plants

The best way to stop the appearance of aphids on pot plants in your grow space is to prevent them from coming near the plants. There are two things you can do about it.

  • Ideally, the grow room should be sealed. If aphids could get in, then it may well be through gaps from a window, vents, or brought in by someone – you. Hence, besides ensuring that there are no gaps from which any insect could crawl in, you should ensure that anything brought inside is clean. Some growers would even take a shower and change into clean clothes before working with the plants.
  • Sticky traps are widely available. You should also have them in the grow room. For one, it helps you detect pests should some be caught. At the same time, it helps eliminate the pests from proliferating early on. You can position the traps strategically – above and beneath the canopy. Besides preventing aphids, they can also help stop other pests such as thrips, whiteflies, and fungus gnats.

In the unlikely event of an infestation of aphids on pot plants, and after confirming that the problem is, indeed, aphids, then it is time to get rid of them for good. You have several options.

Using Chemical Pesticides to Get Rid of Aphids on Cannabis Plants

Some people use chemicals if the infestation is severe, and only during the vegetative stage. The idea is that by the time the plants start flowering, there would not be any chemicals left. There is, of course, no guarantee.

Chemical pesticides do work, and they work fast. One problem, though, is that they are not designed to work with cannabis. Worse, whatever residue left is bound to make its way to us – humans.

Should you use chemical pesticides?

No. Instead, consider the other options that are far safer to the plants, the environment, and people.

Homemade Organic Pesticides

Instead of relying on chemical solutions, you can make organic pesticides at home.

Epsom Salts Spray

  • Mix 1 teaspoon of Epsom salts into 1 liter of water until dissolved.
  • Pour the solution into a spray bottle and spray the plants thoroughly, including the undersides, and the medium.

Garlic and Pepper Spray

  • Dice 250 g of pepper and garlic into small pieces.
  • Add into 1 liter of water and blend for 1 minute using a blender.
  • Let the solution sit for 24 hours.
  • Pour into a spray bottle using a sieve to filter chunky parts.
  • Spray all over the plants and the medium.

As you can see, making a pesticide and using them is super easy. Respray the plants after three days. Do that every three days until there are no longer any aphids on cannabis plants in your grow space.

How to Get Rid of Aphids During Flowering

As the plants approach flowering, you want to avoid using any spray even if it is organic. An infestation of aphids during flowering can be extremely tough to manage as a result of this, but another way to deal with the problem is to use beneficial insects.

Ladybugs are notorious for feeding on aphids and other pests. You can find them in horticultural stores or online. They are cheap, and once released into your garden, feed on the pests without harming the plants. This is probably the most effective way to deal with aphids during flowering.

What Should You Do with the Buds After Stopping Aphids?

After eliminating the aphids on pot plants in your garden, your plants should recover and be on their way to producing a generous yield of trichome-rich buds. One thing you should do while harvesting is to wash the buds and clear off any insect carcass, eggs, urine, and feces.

Prepare three buckets:

Bucket 1: Warm water, 2 tablespoons each baking soda and lemon juice (per liter of water).

Bucket 2: Clear warm water.

Bucket 3. Clean cold water.

After cutting a cola, what you need to do is submerge in the first bucket and gently shake for 20-30 seconds. Remove and before dipping into the next bucket, shake off the excess water. Start with bucket 1, then 2, before 3.

After washing the buds, hang and dry at 18-20°C, 45-55% RH.

Are Aphids on Cannabis Plants Easy to Manage?

Aphids on marijuana is an incredibly annoying problem and, if unmitigated, can be incredibly destructive. Fortunately, they are also easy to wipe out. As you learned, there are chemical solutions that you can use, but they are also dangerous. On the other hand, making Epsom Salts or Garlic and Pepper spray is not tricky, and they are quite effective at stopping pests.

Of course, the best way to stop an infestation of aphids on cannabis plants – and any insects, for that matter – is to prevent them from entering the grow room. That means ensuring that anything brought near the plants should be clean and sanitized. Make sure also that your hands and clothes are clean, too.

Stopping the spread of aphids on cannabis plants and preventing further problems might seem daunting, but, if you follow the guidelines in this article, you should see the problem improve and eventually disappear.