8 Lesser-known Pests You Must be Wary of While Growing Cannabis

Growing cannabis is a delicate art that requires a lot of attention to detail. However, growers often miss one of the biggest threats to their cannabis plants — harmful pests. These pests can wreak havoc on your cannabis plants if you’re not careful.

Perhaps, you’re already aware of various pests that destroy cannabis plants. You may have encountered spider mites and their might and determination to single-handedly kill your beloved herb. 

And, if you’ve been lucky enough to never experience a pest attack, there’s always the Internet that tells you everything you need to know about most pests that attack cannabis plants. Although you can find lots of information about common pests like spider mites, some pests often go undiscussed. But there’s no doubt they can be just as dangerous for your cannabis plant.

In this article, we’ll take a look at some of the lesser-known cannabis pests that you must be aware of, along with tips on how to identify and control them. Of course, we will also give you a quick introduction to other common pests so everything’s in one place and you can refer back to this article whenever necessary. 

Let’s get started. 

Why Should You Get Rid of Pests on Your Cannabis Plant?

Once you grow a couple of plants without the presence of pests, it’s natural to wonder if it’s really that important to get rid of pests. After all, you’ll harvest the plants in a short while, and there’s no need to get so worked up for just a few tiny insects, right?

Wrong. 

The fact is that even if your plants are somehow unharmed by pests magically, they will remain there to relish the next batch of plants. Typically, you can harvest autoflowers even after a pest attack because they grow very fast. If the pests attack the plants late during the flowering stage, you can just spray them down with soap water (avoid spraying the buds) and call it a day. However, the pests will attack the next batch if you don’t clean the area. Therefore, there are various reasons to eliminate pests as soon as you see them. 

1. To protect the health of the plant

Pests can damage the plant's leaves, stems, and roots, making them weak and more susceptible to other problems, such as mold or fungal infections. For example, spider mites can cause yellowing and webbing on leaves, while aphids can cause leaf curling and stunted growth. If pests are left unchecked, they can cause severe damage or even kill the plant.

2. Maintaining plant vigor

Pests can drain the plant's energy and resources, reducing growth and yields. Additionally, the stress caused by pest infestations can make the plant more vulnerable to other issues, such as nutrient deficiencies or disease. Simply put, you can ensure that the plants grow to their full potential and produce high-quality buds by controlling pests. 

3. Preventing the spread of disease

Some pests can transmit viruses and other diseases to cannabis plants, which can quickly spread and cause significant damage to the entire grow operation. For example, thrips can cause yellowing, necrosis, and wilting of leaves. Therefore, it’s important to control their population to reduce the risk of disease transmission and protect the health of the plants.

4. Ensuring the safety of the final product

Pests can leave excrement and other residues on the plant, which can contaminate the final product and make it unsafe for consumption. For example, spider mite excrement can be toxic and cause respiratory issues if inhaled. By controlling pests, you can ensure that your cannabis is safe and free from harmful contaminants.

5. Protecting the growing environment

Pests can infest not only the plants but also the growing area, laying eggs and potentially causing future infestations. In addition to damaging plants, pests can also damage equipment and infrastructure, leading to costly repairs or replacements. By regularly monitoring and controlling pest populations, you can protect their growing environment and maintain a healthy, productive operation.

What are the Lesser Known Pests that Attack Cannabis?

Apart from the common pests that attack cannabis plants, like aphids, thrips, and spider mites, there are many more pests that your plant may suffer from. You may already know the common ones, but here are some pests that you may have never heard of but must be wary of nonetheless.

1. Barnacle Scales

Barnacle scales, aka cottony cushion scales, are lesser-known but common pests that can cause significant damage to plants, including cannabis. These insects are small and oval-shaped, ranging in colors from light yellow to brown. And the reason why they are called cottony cushion scales is because they look like cotton.

If your cannabis plant is attacked by barnacle scales, you will find them hanging out on the stems and leaves of your plant, where these insects feed on plant tissue. Due to this, they rob your plant of necessary nutrients, leading to various symptoms. The primary symptom is the leaves turning yellow and wilting. 

Sometimes, these insects also leave behind honeydew, a sticky residue, which can attract other pests (like ants) and even lead to the growth of sooty mold. And in severe cases, these pests can cause other problems like leaf drop, stunted growth, and even death of the plant. 

If you suspect barnacle scales on your cannabis plant, look for cotton-like masses on the stems and leaves of your plant, along with a possible presence of sticky residue or mold. If you find this pest, you must act quickly by isolating your plant and removing the pests by hand. 

If a part of your plant is heavily infected by this pest, don’t hesitate to prune the area as soon as possible. You can also use neem oil or insecticidal soap to eliminate them or take the help of beneficial insects like parasitic wasps, ladybugs, and lacewings. 

Since prevention is better than cure, it is always better to prevent barnacle scales by keeping your grow room sanitized and clean. You should also regularly inspect your plant for any signs of pests. 

2. Broad Mites

Another pest that you may come across while growing cannabis is the polyphagotarsonemus latus, or broad mites, which are tiny insects that can severely affect your cannabis plants. These pests target many crops apart from cannabis, too, and are usually found in warm and humid places — like your cannabis grow room.

Essentially, these tiny insects feed on your plant’s sap and tissue, thereby robbing the plant of necessary nutrients and inflicting wounds on the surface. Over time, this can lead to your plant’s leaves deforming, slow growth, and eventually death. Other symptoms of broad mite damage include twisted or slow new growth, wet-looking leaves, and sticky buds. 

Since these pests are tiny, they are difficult to detect with the naked eye. Generally, they only grow up to 0.2 mm and have a round body with short legs. Their color ranges from yellow to black. So, don’t confuse the symptoms with heat stress, overwatering, or pH imbalance. If you find these symptoms randomly springing up on your cannabis plant, take out your magnifying glass and start looking for broad mites.

The most effective way to eliminate these pests from your cannabis plant is to use neem oil, insecticidal soaps, miticides, or diatomaceous earth. If you’re using miticides, like abamectin or spiromesifen, follow the manufacturer’s recommendations and practice caution, as these chemicals may harm beneficial insects. 

3. Crickets

You may not think of crickets as a harmful pest to your cannabis plant, but their damage will surprise you. Crickets, if they are in the mood for some cannabis, can eat through the leaves and stems of the plant, leaving gaping holes all over your plant. This can not only damage your plant but also make it susceptible to other pests and diseases. 

If you find holes in your plant’s leaves and stems, look for crickets. Since they are more active at night, you may find them wandering about your plant at night, and you may also find their droppings around the base of your plant. 

Crickets can be a nuisance, but fortunately, they are relatively easy to deal with. To begin with, you can use natural insecticides like neem oil or pyrethrin or introduce beneficial insects like spiders or praying mantis to your grow room to keep the cricket population in check. And to prevent them, keep your grow room clean and plants spaced out, and place nets, screens, or yellow sticky traps around your grow room to deter them. 

4. Planthoppers

Planthoppers are known to suck the life out of cannabis plants while leaving behind cotton-like growth and spreading many diseases. Planthoppers, as their name suggests, are known for their ability to jump short distances, which makes them difficult to control once they attack a plant. 

Planthoppers are a nuisance when they infest your cannabis plant. But how do you spot them? One of the primary symptoms of planthoppers is the growth of white fuzzy masses, which resemble mold, on the surface of your plant. You may also find these insects walking around, but they may look very different depending on their life stage. 

Typically, planthoppers are green or brown and range between 1 to 5 mm in length. Many growers even confuse them for thrips or aphids, but these have a different, unique wing structure that resembles leaves. 

Controlling planthoppers once they attack a cannabis plant is difficult. You’d be surprised how far these tiny insects can jump despite their slow walking speed. So, the most effective way of treating a planthopper infestation is to use spinosad, neem oil, insecticidal soaps, or beneficial insects like lady beetles, lacewings, and parasitic wasps. 

And to avoid planthoppers from ever attacking your plant, you must keep your grow room clean and regularly inspect your plants for any signs of planthoppers. You can also use physical barriers like screens to deter them. And don’t forget to clean any weeds (not cannabis!) or debris from your growing space. 

5. Leafhoppers

Another pest that is similar to the planthopper is the leafhopper — both pest species are quite similar and easy to confuse, but planthoppers are generally broader with flatter sides. Apart from that, leafhoppers are thin and small, wedge-shaped pests that also feed on your plant’s sap. 

Leafhoppers, like planthoppers, can cause significant damage to your plant by robbing it of essential nutrients. This can lead to stunted growth, distorted buds, yellowing of leaves, and much more. And even these pests secrete honeydew, which can attract other insects or black mold. 

The best way to eliminate leafhoppers is to use neem oil or a similar insecticidal soap or introduce predatory mites or insects to your grow room, like ladybugs and lacewings, which will feed on leafhoppers. 

6. Stink Bugs

Stink bugs are relatively common compared to many other pests on this list, which are known to attack cannabis plants during the flowering stage. This makes them dangerous as they can damage the buds and cause significant yield loss or affect the buds’ quality. 

Fortunately, stink bugs are easy to identify by eyes and nose. They have a shield-shaped body and, when disturbed, release a distinct odor — they are called stink bugs, after all. And they have a piercing-sucking mouthpart that allows them to feed on your cannabis plant’s sap. 

As a result of their feasts, your cannabis plant may suffer various problems, such as yellowing or wilting of leaves, damaged flowers, or weakened stems, depending on when and where these bugs attack. 

If you find even a single stink bug in your garden, you must act immediately to eliminate them. Start by cleaning your grow room and removing any weeds or old leaves from your grow space. Then, if you spot any stink bugs anywhere, start by removing them by hand. 

Don’t worry, stink bugs are cute and harmless for humans, and it is recommended to remove them instead of squishing them or spraying them with an insecticide. They may release a nasty odor when agitated, which will stink up your grow room, and their dead bodies may attract other pests. 

If you find stink bugs in your garden, you may also find their eggs, which look like patches of white circles. Remove and dispose of any leaves with stink bugs on them and be very careful while doing so. You can also give your plant a spray with clean water to wash off any leftover eggs or bugs. 

As a final resort, you can use neem oil or another insecticide to remove them. But this option is only recommended if you have a major infestation where picking them off by hand may be too cumbersome. You must also regularly monitor your cannabis plants, so you can spot and eliminate them before they turn your plant into a republic of stink bugs. 

7. Springtails

Springtails are tiny, wingless pests belonging to the Collembola order and are often found in soil or other moist environments. And they are relatively common in humid cannabis grow rooms. These pests don’t directly harm the cannabis plant, but they can be a nuisance to deal with nonetheless. 

So, how are they dangerous? Springtails feed on decaying organic matter, algae, and fungi in the soil. This can be a good thing, but if they grow in numbers, they can start feeding on roots or make the soil more compact, which can affect the water and nutrient uptake for the plant. They may also attract other pests like thrips and mites, which can further damage your cannabis plant. 

Springtails measure less than 6 mm in size and are typically white, gray, or black in color. And they have six legs. You can find them scurrying about in the soil or water trays of hydroponic setups, and you may even see some of them jumping really high, which is how they get their name.

If you do have a springtail infestation on your cannabis plant, you can eliminate them in a few ways. The first method is to use beneficial nematodes, like Steinernema feltia, which can control the springtail population within the soil. You can also use diatomaceous earth, which works as a natural pesticide to kill springtails. 

And to prevent them from getting to your plant by keeping your grow room clean and free of decaying plant matter. They won’t come looking for food in that case. You should also maintain ideal relative humidity in your grow room, along with good ventilation, and avoid overwatering your plants. Moist soil is more likely to attract springtails. 

8. Root Aphids

Root aphids are another small, sap-sucking pest, but unlike other pests on this list, these insects feed on your cannabis plant’s roots. And since they live under the substrate, they are usually difficult to detect until it’s too late. Root aphids can eat away the roots, causing stunted growth, nutrient deficiencies, yellowing of leaves, and even death of your plant. 

Another aspect that makes it difficult to identify root aphids is their small size. And they multiply quickly. They can double in population every 1.6 days in optimal conditions. 

So, a good way to know if you have a root aphid problem is if you find sticky residue on the roots, which is honeydew that can also attract ants or other pests. You may also notice signs of nutrient deficiencies on your plant without a clear cause, like wrong pH levels, nutrient problems, or diseases. 

There are three ways to eliminate root aphids. The most effective one is using nematodes, which eliminate root aphids under the substrate. Another way to eliminate them is to use fungi, like Beuveria bassiana that can target arthropod pests like aphids and cause white muscardine disease, effectively killing them. You can also use neem oil as a root drench but remember to read the manufacturer’s instructions well before using it. 

In severe cases where your cannabis plant is heavily infested with root aphids, it is recommended that you cut your losses and dispose of the plant entirely. Root aphids can spread quickly, and it’s better to lose one plant than risk all the other plants. 

How to Deal with Pests on Cannabis Plants?

Such pests can be a nightmare for your cannabis plants, but there are plenty of safe, organic approaches to keep them at bay. Here are some of the best ways to eliminate most pests on cannabis plants. 

1. Neem Oil

Neem oil is perhaps the most popular and effective insecticide against most pests that attack cannabis plants. It is extracted from neem tree seeds and fruits, which are native to the Indian subcontinent and other tropical regions. 

Neem oil is natural and effective against trips, aphids, mites, and whiteflies, and it can even treat powdery mildew or black spot. And it is not harmful to beneficial bacteria or your plant. You can use it as a soil drench or a foliar spray, but remember to keep it away from the buds. Neem oil has a pungent odor that can hamper your buds’ natural flavor and aroma profiles. 

It is super easy to use neem oil. Simply mix a bit of neem oil with water, shake the mixture well, and use it as either a foliar spray or root drench. And remember to apply it to your plant every 10 days to keep pests at bay. 

2. Essential Oils

Apart from neem oil, you can also use other essential oils that are almost as effective as neem oil. Some of the most popular essential oils for treating pests on cannabis are peppermint, thyme, and rosemary. 

These essential oils have natural properties that can eliminate or prevent pests. Like neem oil, you can mix a bit of them with water and use them as foliar spray or root drench. Just remember to do enough research on the oil you use, as some can be potentially harmful for beneficial insects or flowering cannabis plants. 

3. Diatomaceous Earth

Diatomaceous earth (DE) is a powdery substance made from fossilized remains of diatoms, a type of marine phytoplankton. It is mostly composed of amorphous silicon dioxide and is quite effective at eliminating an array of pests like ants, fleas, mites, aphids, scorpions, and many more. 

Essentially, diatomite in DE scratches the waxy layer of the carapace of pests, which affects their immunity and dehydrates them, eventually killing them. So, if your plant is suffering from a pest infestation, consider powdering your plant with DE to eliminate the pests.

The only downside with DE is that it works where applied and may not be so effective at eliminating pests that stay hidden under the leaves or within the substrate. 

4. Beneficial Insects

Another effective way to keep pest populations in check in your cannabis garden is introducing beneficial insects, which act as biocontrol agents that prey on harmful pests that may otherwise harm your cannabis plants. Plus, they help make your garden a richer ecosystem. 

Some of the best beneficial insects you can use to eliminate pests from your cannabis plant are ladybugs, green lacewings, parasitic wasps, hoverflies, and praying mantis. And these insects are easy and cheap to source, and they do not affect your cannabis plant in any way!

5. Keep a Close Eye on Your Plant 

Lastly, whether you have already dealt with the pests or want to avoid them entirely, you must be vigilant by keeping a close eye on your plant and maintaining your grow room. Follow these tips to do the same:

• Keep your grow room clean and sanitized at all times
• Remove any dead plant matter, debris, and fallen leaves from the vicinity of your plants 
• Keep all the tools and equipment clean
• Invest in screens or insect traps to deter pests 
• Whenever introducing a new plant to your garden, always quarantine it for a week before introducing it to ensure it is pest-free 
• Grow companion plants like marigolds, lavender, and mint to repel pests 
• Regularly monitor your cannabis plant for any signs of pests or damage

By implementing these techniques, you can greatly reduce the risk of pest infestations on your cannabis plant. 

Common Pests Attacking Cannabis

Now that you’re familiar with the lesser-known pests, let’s take a look at the common pests you’re bound to find in your cannabis garden. 

1. Spider mites

These tiny arachnids can cause significant damage to cannabis plants if left unchecked. They can reproduce rapidly and quickly infest entire grow operations. Spider mites feed on the sap of cannabis leaves, which can cause yellowing, curling, and wilting of leaves. They also produce webs and leave behind excrement that can make the plant appear dirty and unappealing. 

In addition to causing visible damage to plants, spider mites can weaken the plant's immune system, making it more susceptible to other problems, such as mold or fungal infections. Effective control methods for spider mites include using predatory mites or applying insecticidal soap.

2. Thrips

These small, slender insects can be difficult to detect but can cause significant damage to cannabis plants. Thrips feed on the surface of leaves and flowers, causing discoloration, distortion, and necrosis. They can also transmit viruses and other diseases to cannabis plants, which can quickly spread and cause widespread damage. Thrips can be controlled through sticky traps or by applying insecticidal soap.

3. Whiteflies

Whiteflies are winged insects often found in large numbers on the undersides of cannabis leaves. They feed on the plant's sap and produce a sticky honeydew that can attract other pests, such as ants. They can also transmit viruses and cause leaf yellowing and curling. In addition to causing damage to the plant, whiteflies can also lay their eggs in the soil, which can lead to future infestations. You can control whiteflies by using sticky traps or applying insecticidal soap.

4. Aphids

Aphids are soft-bodied insects that can reproduce quickly and cause significant damage to cannabis plants if left unchecked. They feed on the sap of cannabis leaves, causing curling, distortion, and yellowing. They can also transmit viruses and attract other pests. Aphids can be controlled by predatory insects or by applying insecticidal soap.

5. Fungus gnats

Fungus gnats are flying insects that lay their eggs in the soil of cannabis plants. Their larvae feed on the roots, causing damage and stunting growth. Fungus gnats can also transmit diseases and are typically found in moist soil. Effective control methods for fungus gnats include allowing the soil to dry out between watering and using sticky traps.

6. Caterpillars

Caterpillars are larvae of moths and butterflies and feed on cannabis leaves and buds, causing significant damage. They can also leave behind webbing and excrement that can contaminate the final product. Effective control methods for caterpillars include using predatory insects or applying insecticidal soap.

7. Mealybugs 

Mealybugs are soft-bodied insects that feed on cannabis leaves and produce a waxy substance. They can cause yellowing and curling of leaves and stunting of growth. You can control them easily, but it’s best to prevent them instead.

8. Scale insects

Scale insects are small, round insects that attach themselves to cannabis stems and leaves and feed on their sap. They can cause yellowing, wilting, and leaf drop, ultimately leading to small yields. You can control them easily by using neem oil or insecticidal soap.

9. Cutworms

These larvae of certain moths can feed on the stems and roots of cannabis plants, causing damage and stunting growth. They can also cut the stem at ground level, causing the plant to wilt and die. You can control them by using physical barriers or applying a pesticide.

10. Japanese beetles

Japanese beetles can feed on the leaves and flowers of cannabis plants, causing damage and stunting growth. They can also attract other pests and transmit diseases. You can effectively control Japanese beetles using physical barriers or pesticides.

Summary: Lesser-known Pests You Must be Wary of While Growing Cannabis

If you come across these pests — fingers crossed, you don’t have to — you must act immediately. They are not only a nuisance but can effectively kill your plant or at least affect your yield. 

It is crucial to remember that preventing these pests is key to growing healthy cannabis plants. So, use the tips mentioned above to prevent these pests from ever reaching your plant. 

And if they still reach your plant, use one of the many methods suggested above to eliminate the pests. Remember, your best friend when it comes to dealing with pests is neem oil or diatomaceous earth, but you can also use companion plants, beneficial insects, insecticidal soaps, or other essential oils.

Whichever method you use, always remember to follow the right steps and keep anything that may affect your buds’ flavor or aroma away from the bud sites. 

Use this guideline as a stepping stone to becoming a better grower, and look forward to many such articles from us. Stay tuned.