As a cannabis grower, nothing is more frustrating than walking out to check your plants and discovering a swarm of tiny sap-sucking aphids feasting on your precious buds. Aphids, also called greenflies or blackflies, are common marijuana pests that can quickly get out of control. An aphid infestation can stunt your plant’s growth, spread disease, and attract other insects. Fortunately, there are effective organic and natural methods to get rid of aphids and keep them away for good.
What are Aphids?
Aphids are soft-bodied insects that come in many colors like white, green, yellow, black, brown, and red. They pierce cannabis leaves and stems with their needle-like mouthparts, feeding on sap and plant juices. Aphids secrete a sticky waste called honeydew that attracts sooty mold fungus.
Adult aphids can be round or oval-shaped with long legs and antennae. Nymphs are smaller, thinner, and often white or pale in color. Aphids live in dense colonies, usually on the undersides of leaves and on stems.
How Aphids Spread
Winged adult aphids known as colonizers land on plants and begin reproducing rapidly. They can birth up to 10 nymphs per day, which mature in about a week. Aphids are born pregnant, so the cycle continues. When colonies get overcrowded, winged aphids develop to fly off and infest other plants. Even just a couple landing on your pot plants can lead to a full-scale takeover.
Signs of an Aphid Infestation
Catch an aphid problem early by inspecting plants daily. Look for:
- Tiny insects clustered on stems and undersides of leaves
- White molted skins leftover from nymphs
- Yellow, curling leaves
- Sticky honeydew on plants
- Sooty black mold growing on leaves
- Ants harvesting honeydew
8 Ways to Get Rid of Aphids on Cannabis Plants
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Remove heavily infected leaves and buds.
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Knock aphids off with a strong stream of water.
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Apply insecticidal soaps or neem oil every 5-7 days.
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Use organic sprays with spinosad
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Introduce ladybugs or lacewings to eat the aphids.
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Apply diatomaceous earth around the base of the plant
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Use reflective mulches to confuse aphids.
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Treat ants if present to prevent them from farming honeydew.
Always start with the least-toxic solutions first Here’s an in-depth look at how to implement each method for aphid control,
1. Remove Heavily Infested Leaves and Buds
If you spot a small new aphid colony, simply pruning away the badly infested leaves and buds can help control the outbreak before it spreads. Clip leaves with scissors sterilized in rubbing alcohol to prevent transmitting diseases between plants.
Check carefully and remove any leaves or branches with:
- Large groups of aphids present
- Significant yellowing or wilting
- Black sooty mold growth
Removing the most heavily infested plant parts can eliminate many aphids quickly and prevent them from multiplying into an even bigger problem.
2. Dislodge Aphids with Water Pressure
Sometimes simply spraying aphids off plants with water is effective for small or early infestations. Adjustable misters on a hose allow controlling water pressure. Set to high pressure and aim directly at clusters of aphids to knock them loose.
Try this method after applying insecticidal soaps or horticultural oils, which help detach the waxy coating on aphids that makes them cling to plants. The strong water stream washes the dead aphids away.
Focus on the undersides of leaves and base of stems where aphids tend to congregate. Follow up weekly to catch any survivors.
3. Apply Insecticidal Soaps
Insecticidal soaps weaken the outer shell of soft-bodied insects like aphids. Brands like Safer’s Insecticidal Soap and Garden Safe Insecticidal Soap are specifically formulated to target unwanted pests while being gentle on plants.
To work effectively, sprays must coat all infested plant parts to smother the insects. Drench the undersides of leaves and stems where aphids hide. Reapply every 5-7 days for 2-3 weeks until aphids are gone. Avoid getting soap solutions on flowers or buds.
Other natural soaps like Dr. Bronner’s, with the added step of diluting in water first, can work similarly to kill aphids. Stick to liquid soap, not detergent bars.
4. Use Organic Sprays with Spinosad
Spinosad is an organic neurotoxin derived from the fermentation of a soil bacteria. Commercial products like Monterey Garden Spray and Captain Jack’s Dead Bug Brew rely on spinosad’s insecticidal properties to safely knock out aphids and other soft-bodied bugs.
Unlike harsher synthetic pesticides, spinosad carries little risk of toxicity or residue for people, pets, beneficials, or the environment. It’s ideal for an integrated pest management approach.
As a contact pesticide, thorough coverage is vital for best results. Spray liberally on infested leaves, especially undersides, as well as stems, branches, and the soil. Most formulas break down within a week in sunlight so reapplication is important.
5. Release Beneficial Insects
Encourage hungry predators like ladybugs, lacewings, and midges. They devour aphids naturally while posing no threat to cannabis plants or humans.
Buy live ladybugs or lacewing eggs and release near aphid hotspots. Apply a sticky barrier like Tanglefoot around the stem base to keep them on your plant. Provide temporary habitats like reeds bound with string for cover.
Attract natural beneficials by planting pollen and nectar sources like dill, fennel, cilantro, and cosmos nearby. Avoid pesticides toxic to these helpful predators. It takes time for their populations to increase and impact, so have patience. Monitor to supplement with more releases as needed.
6. Apply Diatomaceous Earth
Diatomaceous earth (DE) is a natural mineral dust that cuts into an insect’s waxy outer layer, causing dehydration and death within 48 hours. It’s non-toxic to mammals, so safe for cannabis.
Dust DE powder over the soil, leaf undersides, stems, and on top of growth medium to kill aphids on contact. Reapply after rain or watering.
Be sure to get food-grade DE designed for pest control. Wear a mask when handling to prevent inhaling the dust. Avoid buds and flowers.
7. Use Reflective Mulches
Aphids locate plants by color contrasts. Laying down reflective silver or aluminum mulch creates an optical illusion that can deter winged aphids from landing and colonizing your crop.
The dazzling effect also perplexes ants, preventing them from farming aphid colonies for honeydew.
Alternatively, paint the surface of pots or boards below plants with reflective paints. Refresh anytime the color starts to fade. Note this only repels, not kills.
8. Control Ants if Present
Ants will actively protect and farm aphid colonies in order to feed on their sugary honeydew secretions. Getting rid of ants can allow other beneficials like ladybugs to manage the aphids.
Apply sticky barriers like Tanglefoot around pot rims or stems. Diatomaceous earth sprinkled near ant nests and trails will help diminish their numbers so they abandon the aphids.
Eliminating ant access to plants is key. Hydrophobic powders like diatomaceous earth around pots deter their farming efforts. Keep garden areas clean and remove debris piles where ants take shelter.
Avoid Harsh Insecticides!
It’s tempting to reach for powerful chemical solutions when faced with hordes of sap-sucking aphids devouring your crop. However, many conventional insecticides pose serious health and environmental risks and should be avoided.
Stick to organic-approved treatments that specifically target soft-bodied insects like aphids. Read labels carefully and never apply any product directly to smokable buds or flowers. With persistence and an integrated approach, you can get rid of aphids safely!
When to Call a Professional
If you’ve diligently tried these DIY methods and aphids still overwhelm your plants, it may be time to bring in a licensed pest control expert. Professionals have access to stronger synthetic insecticides that require proper protective gear, techniques, and licensing to apply safely and effectively.
Protect Future Crops from Aphids
The best cure is prevention! Keep aphids off your cannabis plants next season with these proactive tips:
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Monitor plants extremely closely, at least every other day
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Remove any infected plants immediately
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What Causes an Aphid Infestation?
Your plant can become infested when winged “colonizer” aphids land on the plant and lay eggs. Winged aphids are dangerous because they can lay eggs and start a new aphid colony, even if you don’t see them eating your plant. Depending on their color, they are sometimes called “blackfly” or “greenfly” bugs because they look like tiny flies and are usually black or green/yellow.
When they have wings, aphids are sometimes called “Green Flies” or “Black Flies,” but their bodies are pretty much the same. When there are too many aphids in one area, the winged types show up. These bugs use their wings to fly away and lay eggs on other plants. This “black fly” is actually a winged aphid.
This “green fly” is another color variation of a winged aphid
Outside, it’s hard to keep aphids away from your cannabis plants because it only takes a few winged aphids to start an infestation. Soon after the eggs are laid, the aphids turn into “nymphs,” which are young adults that are happy to eat your plant.
This grower started seeing white specks on their buds and thought it might be mold or bud rot. The specks were actually white aphid nymphs. Click the picture for a closeup!.
Immature aphids (nymphs) usually appear white and feed on plant sap while they gradually increase in size.
In seven to ten days, the aphid nymphs become adults and shed their skin, leaving behind silvery shells that stick to your plants. It’s possible that you have thrips if you see tiny white bugs that look more like worms than these ones.
The bottom center aphid is actually in the middle of shedding its exoskeleton in this pic.
Aphids don’t get wings when they’re actively colonizing your plant, so when they become adults, they’re ready to give birth to live young and start the process all over again. Most aphids in this form are female, and each one is capable of producing dozens of offspring.
A few winged aphid “colonizers” can quickly make hundreds or even thousands of offspring, which can cover a plant in a short amount of time. A full-blown aphid infestation can get out of control in just a few weeks!.
For the most part, aphids keep reproducing on a plant until it gets so stressed or crowded that it can’t support their huge appetites any longer. At that point, some aphids start to hatch with wings. These aphids then fly off to find a new host plant and start the whole process over again.
How to Identify Aphids on Cannabis Plants (also called greenflies and blackflies)
Aphids are soft-bodied bugs that like cannabis. They can be white, green, yellow, black, brown, or red, depending on their stage of life and where they live. Because they’re so widespread they can be a cannabis pest almost anywhere in the world!.
Aphids look very different depending on their stage of life. The brighter, rounder bugs in this picture are adult aphids. The thinner, white bugs are young aphids, also called nymphs. Note: If you’re seeing white bugs that look like tiny fat worms, you may actually have thrips.
Sometimes the aphids that attack marijuana are dark-colored or black. This bud is aphid city!
Here’s another example showing aphids of different colors and at different stages of life.
Growers may think they see black flies or green flies on their cannabis when they really see aphids with wings. Winged aphids can be dark or pale, and colors include green, red or yellow. However, the bug’s body shape is usually pretty much the same whether it has wings or not.
Sometimes people don’t know that they are aphids when they are a different color, like these young aphids that look red. This is because many aphids that attack cannabis are green.
These aphids from Europe are pale green with dark legs and red eyes
Aphids are a common cannabis pest. Adults are usually small and oval-shaped and may have visible wings or antennae. Nymph aphids are thin/long and usually white or pale. Because nymphs are so small, they may look like little white specks or eggs.
Aphids pierce cannabis leaves with their sucking mouth-parts and feed on the juices inside. They usually occur in colonies located mainly on the undersides of stems and leaves. If there are a lot of pests on a cannabis plant, the leaves may turn yellow and/or wilt from too much stress and damage to the leaves.
“Honeydew” and Black Sooty Mold
Another problem with aphids is that they make a lot of honeydew, which is a sugary liquid waste. Honeydew drops from these insects attract a type of fungus called sooty mold. If honeydew builds up on your plant’s leaves and branches, sooty mold can grow on it and turn them black. This mold not only changes the color of the plants and sometimes gets in the way of their normal functions, but sooty mold on buds can also make them unsafe to smoke. Plus, the sweet honeydew drops can also bring in other bugs, like ants, which is too much trouble.
How to Kill Aphids on Indoor Plants EASY in Minutes!
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