How to Get Rid of Aphids on Cannabis Plants (and Keep Them Gone)

Aphids are a common pest that can do serious damage to your cannabis plants if you don't get them under control. To get rid of aphids on cannabis, catch them early and hit them with organic sprays like pyrethrins and insecticidal soap (once plants are flowering, use organic products only). Then bring in natural predators like ladybugs and lacewings, and keep your plants stress-free so the bugs don't come back. These tiny sap-suckers stunt growth, deform leaves and leave behind honeydew that invites harmful mold.

Spotting and wiping out aphids on your plants early is key to keeping them healthy and bringing in a heavy harvest.

Here's how to prevent infestations and keep your plants in top shape so they can thrive without aphids breathing down their necks.

What are aphids?

Aphids, whether red, green, white or black, are tiny oval insects 1 to 4 mm long that feed on the sap of cannabis plants. That sap, loaded with the carbohydrates and nutrients the plant needs to grow, is these invaders' main food source.

An aphid infestation can seriously hold your plants back, stalling their growth and shrinking your harvest.

Aphids on weed breed at an alarming rate: females can produce 3 to 10 offspring a day, and the young (nymphs) can live up to 25 days. Winged aphids can hop quickly to other plants, which means they can spread through your entire grow within weeks if you don't stop them.

How do you spot aphids on cannabis plants?

To deal with aphids in a cannabis grow, you first need to learn to recognize them. They can be hard to spot at first because they're small and their color can blend in with the leaves, but there are a few clear signs they've moved in:

1. Colonies on leaves and stems: Aphids usually gather in colonies on the undersides of leaves and along the stems. Look closely at the leaves and you can find the young ones too.
2. Sticky residue (honeydew): Aphids excrete a sticky substance called honeydew that can coat the leaves and attract other insects like ants, wasps and bees. Honeydew is usually a dead giveaway that you've got an infestation.
3. A range of colors and sizes: Aphids come in different colors, including light green, black, gray, white and pink. They're usually no bigger than 4 mm, though some can reach up to 8 mm. Males and females look noticeably different, with females a bit bigger and rounder.
   • Male aphid: Slimmer and longer, with longer, thinner antennae of 5 to 7 segments.
   • Female aphid: Rounder and plumper, with shorter, sturdier antennae of 3 to 6 segments.

How aphids damage cannabis plants

An aphid infestation can have serious consequences for the health of your cannabis plants:

• Wounds on the plant: Aphids pierce the plant's tissue to feed, leaving wounds that can be slow to heal.
• Virus transmission: These bugs spread viruses that can keep plants from flowering properly.
• Stunted growth: The honeydew they leave behind can smother the buds, encourage mold and slow your plants down.
• Leaf deformities: Leaves hit by aphids can yellow, curl, dry out and wrinkle, and a bad enough infestation can eventually kill the plant.

Keeping aphids in check takes constant vigilance and fast action to prevent widespread damage to your cannabis grow.

How to get rid of aphids on cannabis plants

Fighting aphids during the vegetative stage

Aphids can be a stubborn pest on your cannabis plants, especially during veg. The good news is there are plenty of methods and products that knock them out. At this stage, you can go with biological or chemical insecticides, depending on your situation and preference.

Organic insecticides for aphids in veg

1. Organic pyrethrins: A solid option is an organic pyrethrin product like Spruzit. It doesn't just take out adult aphids, it also contains rapeseed oil, which smothers the eggs and helps prevent future infestations.
2. Insecticidal soap: To wash off honeydew and leftover aphid skins, and to prevent sooty mold, spray the leaves with a potassium soap like Mobet. It keeps the leaves clean and lowers the risk of disease.
3. Integrated protection: Pair biological insecticides with products that strengthen the plants and reduce stress, like Actiprot and Cinaprot from Prot-eco. These help plants bounce back faster and blunt the viruses aphids can spread.

Chemical insecticides for aphids in veg

1. Clean out your grow: In indoor grows, if you've had aphids or other infestations like thrips or spider mites, clean out your grow room with Solfac Automatic Forte, an insecticide fogger that sprays automatically. This step is key to keeping the pests from coming back.

How to get rid of aphids during flowering

Once your plants are flowering, stick to biological insecticides, since the buds are sensitive and chemicals can linger in the final product.

1. Biological insecticides: Use proven products like Spruzit, which also kills aphid eggs. These insecticides are safe during flowering and help protect the quality of your harvest.
2. Daily checks: Look over your plants every day, especially the undersides of the leaves. Wipe off honeydew and shed aphid skins with a potassium soap like Mobet to keep the leaves clean and healthy.

Fighting aphids with natural predators

1. Predators: Bring in natural predators like lacewings, ladybugs and hoverflies (for example, Chrysoperla carnea, Chrysopa formosa, Coccinella septempunctata and Adalia bipunctata). These insects help keep aphid numbers down.
2. Parasitoids: Use parasitoid wasps like Lysiphlebus testaceipes and Aphelinus abdominalis, which lay their eggs inside aphids. The larvae grow inside the aphid and kill it.
3. Entomopathogens: Consider disease-causing fungi like Verticillium lecanii, which infect aphids and help shrink their population.

Keep in mind that bringing in natural enemies can be tricky in outdoor grows, so encouraging the local wildlife that's already adapted to your area is a good strategy. Talk to experts to find the right natural predators for your situation.

Put these methods and products to work and you'll keep your cannabis grow aphid-free and set yourself up for a healthy, heavy harvest.

How to prevent aphids in a cannabis grow

Keeping aphids off your cannabis plants in the first place is key to a healthy, productive grow. Here are some effective strategies to keep these bugs from moving in.

1. Check your plants every day

Keeping a close eye on things is one of the best ways to catch problems before they turn into full-blown infestations. Check your plants daily for any change in color or in how the leaves and stems look. That way you'll catch aphids and other problems early.

2. Nail the basic care

Aphids thrive on stressed plants. Make sure your cannabis is getting the right care:

• Watering: Water on a regular schedule and avoid both overwatering and underwatering.
• Humidity: Keep humidity levels in check. Too much humidity can help aphids multiply.
• Ventilation: Give your grow good airflow so heat and humidity don't build up.
• Feeding: Don't overdo the fertilizer, since it can attract aphids.

3. Keep your grow clean

In indoor grows, walk in wearing clean clothes, not the ones you wore outside. That helps keep out parasites and diseases that can turn into pest problems. Good hygiene lowers the risk of infestations and makes for a healthier environment for your plants.

4. Hang yellow sticky traps

Yellow sticky traps are an effective way to detect aphids and other flying insects. These sticky strips attract and trap bugs, so you can keep tabs on pest activity in your grow.

5. Go with biological products

When it comes to getting rid of aphids, biological products and solutions are always the better call. They're less toxic and safer for both plants and people. If you do need a chemical insecticide, only use it during the vegetative stage, so any residue has a good chance of breaking down before harvest.

Put these preventive measures in place and you'll keep your cannabis plants aphid-free and bring in a healthy, heavy harvest. Prevention is the name of the game when it comes to avoiding bigger problems and keeping your grow dialed in.