How to Deal with Common Cannabis Pests?

Remember how, as kids, caterpillars seemed cute? Those tiny, squishy little critters had a charm we couldn’t resist. But when it comes to growing cannabis, these innocent-looking larvae are anything but charming. 

In fact, caterpillars can be one of the worst enemies your plants will face. And they’re not alone. From sap-sucking aphids to burrowing leaf miners, cannabis plants attract all kinds of pests that can seriously mess with your plants if left unchecked. 

So, how do you handle these freeloaders and keep your plants thriving? In this article, learn about the common insects you need to look out for and the best ways of dealing with them. Let’s dive in. 

Risks of Pests in Your Cannabis Garden

So, you’re growing a healthy cannabis plant, watching it flourish, and then you spot a couple of tiny insects here and there. At first, it may not look like much of an issue — it’s just a few insects. However, you must be wary — it’s only the beginning. Worst case scenario, the problem is much, much worse. 

These tiny insects may sometimes seem cute to you, but they are anything but that. They are freeloaders who will take every opportunity to mess up your cannabis plant. And if you don’t deal with these pests, they’ll happily stick around and jump to the next batch. 

But before we get to dealing with them, let’s first learn how they can be dangerous for your cannabis plant. Here’s more on the same. 

• Risk of Mold and Other Fungal Infections

Pests don’t just nibble a little occasionally — they can do real damage. From munching on leaves and roots to weakening the entire plant structure, pests like spider mites, aphids, and thrips love to sap your plant’s strength. 

This can leave your cannabis vulnerable to mold, fungal infections, and a whole bunch of other nasty stuff. Keeping pests at bay is like giving your plants a protective shield so they can stay healthy and strong.

• Reduced Plant Growth and Vigor

Plants need energy to grow, and pests are thieves stealing that energy. When pests attack, they drain the plant’s resources, which can slow down growth, reduce yields, and stress the plant out. 

A stressed plant is more likely to face other issues, like nutrient deficiencies or diseases. By keeping pests under control, you’ll give your plants the best chance to thrive and produce those high-quality buds you’re after.

• Spread of Disease

Pests can carry diseases, acting as little delivery agents for viruses and bacteria. Thrips, for example, can bring yellowing, wilting, and necrosis to your plants, threatening the whole crop. Taking action early means cutting off the pest population before they get the chance to infect your entire crop. It’s all about taking preventive steps to keep your plants disease-free.

• Low-Quality Yield 

Let’s face it, nobody wants cannabis covered in pest leftovers. Pests can leave behind residues and excrement that are anything but safe. Take spider mites, for instance — their droppings can cause respiratory issues if inhaled. 

Pest control not only helps keep your plants clean and safe but also ensures you’re growing cannabis that’s top quality and ready for consumption without any unwanted contaminants.

• Real Risk to the Growing Space

Pests don’t stop at the plants. They’ll lay eggs, make nests, and invade your whole grow area if you let them. This can lead to infestations that damage not just your plants but also your equipment and setup, which can be costly to fix or replace. 

Regular monitoring and pest control keep your growing space clean and functioning smoothly, so you can keep your focus on growing strong, healthy cannabis plants.

Common Cannabis Pests You May Come Across

When it comes to growing cannabis, pests are probably among the most annoying issues you’ll face, especially outdoors. And they’re not just a mild inconvenience — they can wreck your plants differently depending on the pest. So, what should you look for, anyway? 

Cannabis plants attract all sorts of pests, which come in a few common varieties, such as the following. 

• Sap Suckers

Such parasites attach themselves to your plants and drain away vital nutrients. This weakens your cannabis plants and can even mess with their growth and yield. Think of them as the tiny vampires of your garden — they leave your plants looking pale and frail.

• Chewers

As the name suggests, these insects nibble away at leaves, stems, and even buds. This can stunt growth, open the door for infections, and reduce the yield. If your plants look like they’re missing parts, you’ve probably got these munchers on your hands.

• Infection Carriers

Such infectious insects aren’t feeding on your plants directly, but they bring a host of problems like mold, fungus, and diseases along with them. They’re essentially hitchhiking troublemakers that can ruin an otherwise healthy crop.

Common Pests You’ll Find on Cannabis

For a better idea of which pests might be lurking in your growing space, chat with a local grower — they’ll know the usual suspects. Or, ask questions here. But let’s look at some common cannabis pests that you should always be wary of. 

1. Aphids

Aphids are tiny insects with soft bodies. These tiny sap-suckers are major troublemakers in cannabis cultivation. They’re small, but their impact isn’t. They come in a variety of colors, usually green, black, red, or brown. Aphids, like the cotton aphid, green peach aphid, and even the cannabis aphid (yes, that’s a thing) can quickly take over. 

They’re experts in sap-stealing, causing leaves to wilt, growth to slow, and even spreading plant diseases. Spotting these early is key, so keep a lookout for clusters of little green, white, or black bugs.

These insects are pear-shaped and are 1 to 3 mm long. Aphids are easy to see with your eyes and are often found in groups on the stems or under the leaves and on the stems in clumps. There are many types of aphids and each is slightly different in appearance and behavior but they all suck on cannabis sap and pose a risk.

Aphids rapidly reproduce and it goes out of control if your grow room is hot. Thing is, the females can give birth to nymphs even without mating, so it may seem like a lost cause to try and control them. Their rapid reproduction means that colonies can multiply extremely fast, thus making infestations tough to deal with if left untreated. Overcrowded situations will prompt these little critters to develop wings but they can do it even if they feel like moving to another location, rent-free! In short, the infestation can spread all over the grow room or garden.

Aphids are deadly as your cannabis plants become increasingly weak due to a limited nutrient intake. Aphid feeding reduces chlorophyll production, leading to yellowing and fading of the leaves. The leaves may also wilt and curl inward due to the stress. 

When a plant is infested heavily, it stunts the growth which reduces yield and potency. Check for sticky residue, also known as honeydew as aphids produce them on the plants. This residue also attracts ants, so you may see quite a few ants in your grow room if it's infested by aphids. 

Honeydew can also trigger black fungi that grow on plant tissues. They hamper photosynthesis by blocking sunlight which adds more stress to the plant.

2. Whitefly

The winged pests tobacco whitefly and greenhouse whitefly love feeding on cannabis by piercing the plant’s phloem and sucking out the sap. This leads to yellowing and wilting and can even cover leaves in a sticky residue called honeydew, which promotes sooty mold. The result? Less photosynthesis, less yield, and less healthy plants overall.

Whiteflies are small, winged pests that look like tiny white moths. In reality, however, they are more closely related to aphids and mealybugs. Although the insects are tiny (between 1-3mm long) they leave a powdery appearance on the leaves and plants, so it is easy to identify on a cannabis plant. Whiteflies form clusters on the underside of leaves to lay eggs and feed. They often go unnoticed and are difficult to detect until their numbers increase. Warm, humid environments are ideal for whiteflies to thrive, so they are often found in greenhouses and indoor grow rooms.

Coming to their life cycle, whiteflies breed rapidly, especially in grow rooms or tents. The adult female can lay hundreds of eggs on the less visible parts of the leaves which hatch in 5-10 days. Small, transparent, and wingless nymphs emerge and pass through several stages before they reach maturity. Within 20 to 30 days, these nymphs become adults, which starts the cycle again while the infestation can increase rapidly if left untreated.

Whiteflies are sap-sucking pests that steal from cannabis plants and stress them way too much. Like aphids, they also suck chlorophyll and prevent the plants from conducting photosynthesis which inevitably affects the yields. The plant might start wilting, with the leaves drooping due to loss of nutrients, signaling stress. Finally, the infected leaves may fall off as the plant struggles more to survive. 

3. Thrips

Thrips are tiny but mighty troublemakers. The western flower thrip and onion thrip are some of the most common. These pests pierce the surface of your plants and drink up the sap, leaving distorted leaves and stunted growth behind. You’ll notice small spots or streaks on leaves if they are munching away on your plants.

Thrips are tiny, slender insects that measure about 1-2 mm and come in various colors including yellow and brown to brown and black, depending on the species and age of the insect. The small pests which have elongated bodies and fringed wings are also difficult to see sometimes as they are so small. Thrips are usually found on the lower side of leaves where they feed and reproduce. They are stealthy but damaging pests for cannabis plants. 

List most pests, thrips go through a rapid development cycle, especially when in a warm climate. In fact, several generations may be produced in one season. Adult females of this pest lay their eggs directly into the plant tissue where the hatching larvae feed straightaway. After going through several stages, the larvae pupate in the soil or on the plant and emerge as adults after a few days. The population can build up quickly, causing serious issues if you don’t manage them quickly. 

Thrips damage plants by piercing their cells and sucking out their contents, which affects the structure of the plant. The way thrips feed will be evident in the form of damage as you’ll see silvery or bronze discoloration. It’s pretty noticeable as they look like silver and bronze streaks on the plant. Thus, you won’t have any trouble recognizing them.

4. Spider Mites

The infamous two-spotted spider mite might be tiny, but it’s highly destructive. These mites feed on plant cells and leave behind telltale stippling on the leaves. And as they breed fast, they can overrun your crops quickly if left unchecked. Keep an eye out for webbing and yellowed leaves — they’re the signs of a full-blown spider mite takeover.

Spider mites are very small arachnids (related to spiders) that are usually not visible without a hand lens. You'll often notice these mites as red, black, brown, or greenish specks on cannabis plants. Two-spotted spider mites and red spider mites are two types that are usually found on cannabis plants.

Since they are tiny, you may not notice them until it's too late. They are typically just under 1mm in size but since they multiply rapidly, you'll see the damage on the plants. 

Spider mites are mainly seen in indoor grow rooms during the summer because they love hot and dry conditions. Each female lays hundreds of eggs during her lifetime to reproduce quickly and the eggs hatch in a few days. The newly born mite reaches maturity in 5-7 days to become an adult. If conditions are favorable, the population will explode.

Spider mites feed on the chlorophyll in plant cells and damage plant tissues, preventing the plants from performing basic functions, including photosynthesis. This damage affects the overall health of the plant and reduces the cannabis yield. 

So, how do you recognize signs of an infestation? Well, first off, you’ll see small yellow or white spots on the leaves, giving them a stippled or dotted appearance. These are bite marks that you’ll be able to see if you look very closely. If the infestation is serious, the leaves may wither, die, and drop off, causing further strain on the plant.

And, finally, if you haven’t rectified the issue at all, you’ll see a fine, silk-like webbing that covers the surfaces of the leaves, stems, and the entire plant sometimes. The webbing acts as a shield for the mites and their egg from harmful predatory and environmental conditions.

When the infestation goes out of control, you can see the mites with your naked eye but they will look like tiny moving dots, particularly on the underside of the leaves. This doesn’t mean that you can’t see them earlier; actually, you can, but you’ll have to look closely once you notice yellowing leaves or speckled marks on the leaves. 

5. Mealybugs

If you see white, cottony-looking fluff on your plants, that’s likely mealybugs making themselves at home. These bugs sip on sap, leading to stunted growth and yellowing leaves. They’re easy to spot but can be tough to eliminate. 

The worst part? They can attract mold, making an already annoying problem even more problematic.

6. Leaf Miners

Leaf miners burrow through leaves, leaving winding trails behind as they go. Some of the most notorious types include the Tomato leaf miner, Pea leaf miner, and American serpentine leaf miner. 

You can recognize their damage easily — they paint curvy lines on the leaves like artists proudly showing off their work. But, rather than admiring them, you should act immediately as they’re signs your plants are under attack. Leaf miners can seriously reduce a plant’s ability to photosynthesize, weakening it and ultimately cutting down on yield.

7. Caterpillars

These aren’t the cute, fuzzy caterpillars from childhood. Caterpillars like the hemp moth and beet armyworm have quite an appetite, and your cannabis plants are on the menu. 

Hemp moth caterpillars love to burrow into buds, leaving your plants open to bud rot and fungi, while the beet armyworm is the defoliator you don’t want. They strip away leaves, weakening your plants and cutting down on overall vitality.

8. Fungus Gnats

Common in indoor growing, fungus gnats lay eggs in moist soil, where their larvae feed on organic matter, including the roots. This can stunt plant growth, weaken root systems, and raise the risk of fungal infections. If you notice gnats buzzing around your grow room, it’s time to check the soil.

9. Lygus Bug

Lygus bugs pierce plant tissues and drink up the sap, causing distorted growth and necrotic spots. If your plants are looking spotty or blemished, these critters could be the culprits. They can affect the flower quality, making them a pest to watch out for, especially if you’re aiming for top-shelf buds.

10. Other Types of Mites

The hemp russet mites and broad mites are less common but just as damaging. The russet mite distorts plant growth, leading to necrotic spots and poor yields, while the broad mite can trigger yellowing and curling in leaves. Together, these mites can devastate crops if not kept in check.

How to Deal with Pests on Cannabis Plants?

Okay, so now you know what to look for. What do you do when you do find them messing around your cannabis plant, though? You can deal with them in a few days, whether you simply want to be precautionary or wage war against them. Here are some ways. 

1. Use Neem Oil

If you're dealing with cannabis pests, neem oil is perhaps the best natural pesticide available. Used by growers and farmers for ages, it’s a highly effective way to handle unwanted garden invaders without harsh chemicals. Neem oil not only keeps pests away but also helps prevent future infestations.

Neem oil fights off pests in a couple of fascinating ways:

1. Hormonal Disruption: Neem oil is loaded with a compound called azadirachtin, which interrupts the insects’ hormone systems. It messes with their ability to grow, eat, and reproduce, making life tough for them.
2. Mating Blockade: Azadirachtin also interferes with pests' mating behaviors, reducing reproduction rates and eventually leading to fewer pests.

Neem oil doesn’t work like typical pesticides that outright kill pests. Instead, it coats them, preventing them from breathing, and deters them enough to leave your garden alone.

What’s fantastic about neem oil is that it’s completely organic. It’s safe for your cannabis plants but only if you avoid spraying it on the flowers, which could impact flavor. And a bonus? Neem oil doesn’t harm beneficial insects like bees, ladybugs, or earthworms!

Neem oil works against over 200 types of pests, including:

• Aphids
• Broad mites
• Spider mites
• Thrips
• Fungus gnats
• Mealybugs
• Whiteflies

It’s also excellent for preventing fungal and mold infections like slimy roots, as it can help clear out spores more effectively than most alternatives.

How to Use Neem Oil on Your Cannabis?

When using neem oil on cannabis, your best bet is to make a fresh mix at home. Here’s how to prepare it:

1. Look for 100% pure neem oil, as cold-pressed varieties retain azadirachtin. Avoid other types of oil involving heat as they may lack this active ingredient.
2. Neem oil needs help to mix with water. Use silica, organic insecticidal soap, or potassium soap to help the oil blend smoothly.
3. Add a teaspoon of the emulsifier to a gallon of water and then stir thoroughly.
4. Add four teaspoons of neem oil to the container and start shaking it.

Your neem oil mixture won’t stay effective after eight hours, so use it quickly. Because some strains can be sensitive to this pesticide, do a small test on one leaf first. Wait 24 hours to see if the plant shows any adverse reaction.

Remember, neem oil has a pungent smell, so don’t spray it on the flowers as it could affect the taste. Instead, lightly spray only the stems and leaves. Avoid soaking the plant, and don’t use it three weeks before flowering to maintain the plant’s natural flavor.

2. Alternative Pesticides for Cannabis Pests

In some instances, neem oil might not be ideal, particularly if your plants are stressed by nutrient deficiencies, irregular watering, or extreme temperatures. Here are some excellent alternatives to neem oil that still provide effective pest control without compromising plant health.

• Spinosad

This is a great organic pesticide you can use instead of neem oil that’s safe for plants, pets, and children. Manufacturers ferment a soil bacterium to produce this, and it targets pests by disrupting their nervous systems upon ingestion.

Using spinosad is straightforward — just add it to water and start spraying on pest-infested parts, such as the underside of the leaves. 

It’s ideal for dealing with crickets, grasshoppers, aphids, thrips, caterpillars, and spider mites. However, it can harm bees for some time after application, so use it after sundown to avoid impacting these essential pollinators.

• Horticultural Oils

Horticultural oils, derived from plant oils, are another natural pest deterrent that won’t harm your cannabis plants. Unlike neem oil, these oils don’t create a lasting film, making them gentler for sensitive plants. 

However, their effects are short-lived — lasting around 7 to 8 hours — so they require consistent application. Horticultural oils are best used with a mister and need regular reapplication to eliminate all pests.

• Diatomaceous Earth (DE)

Diatomaceous earth, aka DE, is a unique, natural powder formed from the fossils of diatoms, which are ancient algae-like organisms. DE offers multiple advantages for cannabis plants:

• Its abrasive and absorbent nature dehydrates and cuts through pests’ exoskeletons, causing them to die
• DE improves soil moisture, nutrient retention, and oxygen flow, making nutrients easier to consume for the plant due to its silica content

To use DE on your cannabis plant, simply dust it lightly at the base or on the soil of your plant. This will keep the plants at bay. However, DE doesn’t work on wet soil, so make sure your soil is dry when you apply it

These alternatives offer effective, plant-safe solutions for cannabis growers looking for flexibility in their pest control strategy..

3. Grow Companion Plants for Cannabis Pest Control

Companion planting is a natural, eco-friendly way to protect your cannabis from pests and even improve plant health. This method involves growing specific plants around your cannabis, creating a mini-ecosystem where plants support one another. 

Think of it as growing friends for your cannabis, forming symbiotic relationships that benefit the whole garden. Interestingly, this approach is part of permaculture, which aims to create an interconnected system of plants and animals that reduces the need for added nutrients.

Companion plants can deter pests in two ways: they either repel pests with strong-smelling oils or act as decoys that distract pests from cannabis plants. This keeps harmful bugs away while encouraging beneficial insects and enriching the garden environment.

In addition to pest control, companion plants bring various benefits:

• Some plants prevent the spread of fungal spores, safeguarding your cannabis
• Nitrogen-fixing plants enhance soil health, making nutrients more accessible to cannabis
• As part of permaculture, companion planting is 100% natural
• Certain aromatic plants can subtly enhance the flavor of cannabis buds
• Taller plants can help conceal cannabis, reducing visibility and masking its scent

Here are some effective companion plants you can grow around cannabis:

• Lavender — Diverts pests, attract pollinators
• Sunflower — Deters pests
• Peppermint— Repels pests, masks cannabis odor
• Marigold — Naturally repels many pests
• Clover (Red and White) — Fixes nitrogen, controls weed growth, improves soil health
• Basil — Enhances bud flavor, repels pests, and masks odor
• Thyme — Protects cannabis from fungi
• Chamomile — Deters pests, prevents fungal spores, fixes potassium and calcium
• Oregano and Coriander — Repels pests and attracts beneficial insects like ladybugs and lacewings

4. Or Use Beneficial Insects

Beneficial insects are another great way to control pests. These predatory insects hunt and consume harmful pests and their larvae, providing around-the-clock pest control. They not only protect cannabis but also create a thriving garden ecosystem, offering a chemical-free solution to pest management.

Beneficial insects might already be present in outdoor gardens. If not, you can purchase them from horticulture stores or attract them by growing certain companion plants, such as oregano and lavender. 

Identifying common pests in your area helps you introduce the right beneficial insects for the job. Still, here’s a quick list of beneficial insects and the pests they target:

• Ladybugs: Aphids, moths, thrips, mites, beetles
• Predator Mites: Spider mites
• Praying Mantis: Aphids, caterpillars, flies
• Rove Beetles: Fungus gnats
• Nematodes: Fungus gnats, ants, weevils, slugs
• Green Lacewings: Aphids, thrips, spider mites, whiteflies, leafhoppers

By creating a balance of plants and insects, you can maintain a healthy cannabis garden without needing harsh chemicals, fostering a rich, self-sustaining ecosystem.

Tips to Use Pesticides Safely on Cannabis

While organic pesticides are safer than synthetic ones, they still need careful handling to protect your cannabis plants. Here’s how to use them effectively.

• Identify the Pest First

Correct identification of the pest is essential. This helps you choose the right pesticide for the issue and avoid unnecessary applications.

• Research and Seek a Second Opinion

Before trying any pesticide, research thoroughly and consider talking to experienced growers on platforms like Growdiaries. A second opinion can confirm the best approach and prevent potential mishaps.

• Follow Directions Closely

Always apply pesticides exactly as directed. Instructions are carefully prepared by experts, so following them ensures you’re using the product safely and effectively. If you still think that instructions call for more than what’s required, you can always start with a small administration and see how it goes. 

• Avoid Mixing Pesticides

Combining different pesticides can overwhelm and damage your plants, even if they’re organic. Only mix pesticides if advised by the manufacturer or experienced growers.

• Perform a Patch Test

For any new pesticide, apply a small amount to a single leaf and monitor for a day. This helps you detect any adverse effects on the plant.

• Check for Side Effects

Some pesticides may have implications for users. Research side effects to ensure your buds remain safe and enjoyable for consumption.

These tips will help you use organic pesticides safely, ensuring both effective pest control and healthy cannabis growth. 

Summary: How to Deal with Common Cannabis Pests?

When it comes to cannabis pests, prevention and timely action are key. By keeping a regular eye on your plants, using natural pesticides, or even employing helpful insects, you’ll keep pests from spoiling your growth. 

Whether you’re an organic grower with a passion for natural solutions or a first-timer navigating pest control, remember — healthy plants are happy plants. With the right care, you’ll enjoy a lush, pest-free garden and the satisfaction of a high-quality yield.