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Cannabis pests

How to deal with cannabis pests effectively

Over the last two decades, cannabis has seen a meteoric rise in popularity worldwide, but humans aren’t the only species fond of this miraculous herb. Various unique cannabis pests also seem to enjoy the magic of marijuana.

Cannabis pests and diseases can easily ruin entire crops and destroy livelihoods. Dealing with weed bugs doesn’t necessarily lie in chemical warfare, though. There are many less ecologically harmful and more effective alternatives at your disposal if you know your enemy.  

Read on as we take a closer look at the dangers of cannabis pests, how to identify and deal with them, and what to do to prevent future marijuana bug infestations.

Cannabis pests

Sooner or later, every cannabis cultivator will have to deal with bugs on their weed plants. 

Throughout the growing process, from the vegetative stage to harvest, you’re likely to encounter various cannabis pests, such as aphids, spider mites, ants, mealybugs, moths, and caterpillars. If left unchecked, a weed bug infestation can quickly destroy your entire crop.

Cannabis pests

The key to successfully controlling such an outbreak is cannabis pest identification. By correctly identifying which cannabis bugs threaten your crop and familiarizing yourself with their natural predators, you can make the environment naturally inhospitable to these pests. Alternatively, you can use safe organic detergents.

Be careful of the method you use to deal with the marijuana pests, though. Pesticides may seem like a convenient solution, but they can end up doing more damage than good, often making your buds unsafe for human consumption.

The dangers of cannabis pests

Scientists speculate that the marijuana plant may have originally developed THC as a type of cannabis pest deterrent. Mammals would come along, chew on the flowering cannabis plants and soon start to feel disoriented and dizzy. The likelihood that they’d come back any time soon for another taste is slim.

Insects don’t react in the same way. Instead, bugs on marijuana plants seem to love and thrive on THC. What makes these pests so dangerous is that they tend to move in groups and rapidly multiply, meaning that your entire crop can get wiped quickly. 

To make matters worse, the various cannabis pests affect or attack different parts of your weed plants. 

Growing marijuana outdoors puts your crop at higher risk of attracting cannabis diseases and pests due to being constantly exposed to the elements and the various critters and bugs that typically inhabit forests, fields, and gardens.

While indoor grows are more protected, they’re still vulnerable to weed pests. Although there are various means for these unwanted elements to find their way inside, introducing new clones is the most frequent reason for an infestation to take hold. 

Taking caution and implementing measures to try and prevent infestations are of the utmost importance. It’s crucial to know how to spot a weed pest invasion should one occur and know how to deal with it effectively. Also remember, not all insects are a threat to cannabis, making it important to familiarize yourself with the ones that are.

The different types of cannabis pests

Weed pests can be as devastating to your marijuana plants as any other cannabis deficiencies, if not more so. 

Let’s have a gander at the most insidious common cannabis pests out there before we look at how to eliminate them from your precious plants.

1: Aphids

Aphids are tiny, soft-bodied cannabis insect pests. Depending on which stage of their life they’re in, they can be pale red, brown, yellow, green, white, or black. They hide on the underside of marijuana leaves, feeding on leaf sap, ultimately draining the plant’s nutrients.

Telltale signs of this cannabis pest invasion are colonies under leaves and stems, honeydew (a sweet liquid,) and yellowish blades. 

Fortunately, these weed bugs have natural predators, such as Aphid midges and parasitic wasps, that feed on them. You can also crush or remove them manually.

Cannabis pests

2: Bud rot or mold

Bud rot (botrytis) is a kind of mold that forms in the compacted cores of marijuana buds. This weed pest typically appears during your plants’ flowering stage. It starts inside the cola on its stem, gradually spreading outward, making it extremely difficult to detect when developing. 

This type of marijuana pest appears white and wispy. As the cola starts to become mushy and slimy, it’ll turn grey and black.

To detect mold, keep an eye out for it when breaking apart the buds. You can also identify it by smell. It typically gives off an old, wet, and musty fragrance that’ll leave a sour taste in your throat. If you find infected buds, get rid of them immediately as they’re unsuitable for consumption.

Here are some tips to help prevent and stop this cannabis pest:

  • Ensure that your crop gets proper air circulation.
  • Don’t allow your plants to sit in wet, overly humid conditions.
  • If your plants are extremely bushy, defoliate them at the bottom and middle to reduce the humidity around them.
  • Bud rot tends to attack the largest, most dense colas first, so keep a close eye on those.
  • Remove any affected buds immediately, but be careful not to let the rot touch other plants, as the mold spores can spread quickly.

Other types of mold include powdery mildew, sooty mold, fusarium, and mold in the soil.

3: Broad mites

Due to their microscopic size, broad mites are one of the most difficult marijuana plant pests to identify. To add to the confusion, these tiny nuisances can easily be mistaken for root problems, pH imbalance, overwatering, or heat stress.

Symptoms related to these cannabis bugs include:

  • Twisted or drooping new growth
  • Blistered or “wet-looking” leaves with turned-up edges
  • Concentrated attacks, meaning that the symptoms are worse in certain spots
  • Sickly and dead buds if attacked during the flowering stage

To rid your crop of this weed bug infestation, you need to stay vigilant. 

  • Immediately remove the shrub’s infected parts.
  • Treat your crop regularly before lights out with an eco-friendly solution like neem oil or essential IC3. 
  • Introduce predatory mites, such as the Neoseiulus type, to help reduce this weed pest population. 
  • Repeat treatments once weekly for at least five weeks after getting rid of the mites.

4: Caterpillars

Caterpillars have a voracious appetite and need to vegetate to form their chrysalis. These cannabis pests, if undetected, can do a considerable amount of damage to your crop.

Telltale signs left by these bugs on your marijuana are black droppings on leaves, small teeth marks, and yellow or translucent eggs. 

Fortunately, these outdoor cannabis pests are easy to spot and remove by hand. You can also introduce spined soldier bugs or Trichogramma wasps to your garden or apply a garlic and pepper pesticide to your shrubs.

5: Crickets

Crickets are noisy weed pests that’ll happily graze on your marijuana plants, typically leaving small holes in your leaves. They usually live among the branches, and mole crickets can normally be found digging around your crops’ roots. 

The sound that crickets make and their distinct bite marks on your plant’s leaves is a dead giveaway of the presence of these bugs in your weed. 

You can easily eliminate this cannabis pest by using pest control solutions such as spinosad combined with pyrethrin-based products, insecticidal soap, and neem oil treatments. 

6: Leafhoppers

With over 20,000 leafhopper species, it can be confusing to identify these bugs on your marijuana plants. They come in various colors, and their body and head shape can be different, yet their overall structure is always the same—they have six legs and wings, and they can jump and “slide” sideways when moving.

While these marijuana bugs happily suck the sap from your weed plants’ leaves, they spread disease and leave clusters of pale spots behind that gradually turn bronze. 

To get rid of these pesky weed bugs, spray your infected plants with an organic compound such as insecticidal soaps or neem oil, or introduce beneficial insects like lacewings or ladybugs. To keep them out, you can also use floating row covers in your garden.

7: Grasshoppers

Grasshoppers and locusts live amongst the branches of your weed plants while munching on your shrubs’ leaves, leaving sizable holes in their wake. These cannabis pests can also chow through stems, killing entire branches. 

The best way to eradicate these bugs in your cannabis garden is by spraying your crop with an organic pesticide such as spinosad or insecticidal soap. You may also want to consider installing floating row covers to help keep these ravenous pests out.

8: Leaf miners

Adult leaf miners typically look like your common house-fly. These marijuana bugs lay their larvae under your shrubs’ leaves. After hatching, they tunnel through the tops of the blades while draining out vital nutrients and damaging cells. 

This cannabis pest’s unique calling card involves leaving long brown or white streaks across the tops of your plants’ blades.

To exterminate this weed pest infestation, begin by preventing adult leaf miners from laying eggs—place adhesive strips near your crop. To get rid of the bugs, you’ll need to seek them out and manually squish them, one by one.

9: Fungus gnats

Fungus gnats are tiny flying cannabis pests that typically hover around your weed crop close to the ground. Their larvae grow in saturated soil, and they commonly appear if the topsoil around your shrubs stays wet for prolonged periods. 

These weed bugs cause significant damage to your plant’s stems and roots in both their larval and adult phases. They begin by devouring fungus at the base of the weed shrub, then munch their way downwards into the rootstock, resulting in your cannabis becoming structurally unsound with a reduced growth rate. 

To eliminate this marijuana pest invasion, start by placing a sticky pad near the weed plant’s base to catch the larvae, reducing their numbers significantly. Next, mix a small amount of peroxide with water and apply the solution to the region where these bugs are congregating.

10: Mealybugs

Mealybugs are white and hairy cannabis plant pests that enjoy warm temperatures. Be careful with this type of infestation, as these bugs tend to grow and spread even when drying after harvest. 

An invasion of these bugs on pot plants is typically identifiable by the white mold-like powder or webbing patches they leave behind. They usually also produce honeydew which attracts ants and causes sooty mold.

Exterminate this marijuana pest by using water spray to remove as many as you can. Next, start applying eco-friendly pesticides like neem oil and insecticidal soaps, one at a time. Alternatively, you can sprinkle diatomaceous earth over the infected soil and introduce beneficial insects like lady beetles and ladybugs to your garden.


11: Planthoppers

A planthopper’s physical appearance changes dramatically throughout its life. There are also many different species of this weed pest, and they come in various colors. Still, their general form remains the same, resembling a leaf or another part of your marijuana plant. Although they move slowly, they can jump surprisingly far.

As this common cannabis pest infests and attacks your weed, it sucks it dry and spreads disease. They leave a white fuzzy secretion behind that’s easily mistaken for powdery mildew or mold. The main symptom is sickly, yellow plants.

To prevent these cannabis bugs from invading your crop, install floating row covers. If the infestation has already taken hold, you can introduce beneficial insects to your garden or eliminate them with an organically formulated pesticide such as spinosad or neem oil.

12: Root rot

Unwanted pathogens in your hydro tank are the usual suspects when it comes to cannabis root rot.

This marijuana pest results in an unhealthy, slimy, brown, and twisted rootstock, preventing your weed plant from getting enough oxygen and nutrients. Various organisms, such as different types of oomycetes, algae, fungi, and bacteria, can cause this infestation.

Typical signs of these marijuana plant pests include:

  • Drooping weed plants
  • Yellow or white leaves which die and fall off
  • Brown, smelly, or slimy roots

Although this weed pest infestation isn’t easy to get rid of, there are methods to eliminate them. You’ll need to:

  • Directly treat the weed plant’s rootstock with a solution, such as beneficial root bacteria or hydro guard.
  • Ensure there’s enough oxygen in the water.
  • Ensure that your DWC reservoirs are completely void of light.
  • Keep your grow room cold.
  • Avoid disturbing your weed plants’ roots.
  • Keep the entire grow environment extremely clean and sterile.

13: Slugs and snails

Snails and slugs are common bugs on marijuana plants. Identifying their presence on your crop is easy; look for the shiny, translucent mucus trails they leave behind. 

The best way to get rid of these weed bugs is to remove them manually. Alternatively, you can:

  • Construct a barrier around your crop
  • Place baits and lures 
  • Introduce Rumunia decollate, a predatory slug, to your weed garden

14: Russet mites

Russet mites are tiny bugs on pot plants that often appear as a yellow or beige mass. They live in the crevices of the buds, stems, and leaves and can easily be confused with various other issues.

Telltale signs of these bugs on your marijuana plant are:

  • Yellow or beige-looking weed shrubs
  • Curled leaf edges
  • Drooping foliage
  • Brittle and dull-colored stems or blades
  • Leaf stress in the form of brown or yellowish spots

Eradicating these is very challenging, as these cannabis bugs lay their eggs inside the weed plant. To effectively deal with this issue, you need to:

  • Treat your crop regularly with a miticide, such as essential IC3 or Mighty Wash, before lights out.
  • Re-apply treatment once weekly for at least five weeks. 

Alternatively, you can introduce predatory mites to your marijuana crop.

15: Spider mites

One of the most commonly found bugs in weed cultivation is spider mites. These small red pests reproduce rapidly and reach full maturity within seven days. They can swiftly overrun your crop, sucking out chlorophyll and valuable nutes, quickly destroying your entire harvest.

These marijuana bugs are usually identifiable by the signature white spots they leave on the blades, accompanied by black or yellow dots on both sides. When examining the evidence, using a magnifying glass is advisable as these symptoms may be confused with a nutrient deficiency.

There are several different natural remedies at your disposal to deal with this weed pest. Predatory insects, such as Ladybugs, enjoy having spider mites for dinner. You can also spray these bugs using an alcohol (or neem oil, potassium salt, etc.) and water solution to knock them off your cannabis shrubs. 

16: Thrips

Thrips are hard to spot, fast, and tiny cannabis pests that’ll happily devour your weed buds. With the flower as their main source of food, your shrubs won’t be able to mature properly, reducing your overall yield. Apart from eating your precious plant, they’re also known for spreading diseases. 

To identify this weed pest invasion, you can either use sticky strips or look for silver markings on your shrubs’ surface and brittle leaves.

If you detect this marijuana bug before the flowering stage begins, you can spray your crop with neem oil or potassium soap. Otherwise, alternative pest control measures, such as predatory wasps or insidious flower bugs, are a better option.

17: Tobacco mosaic virus

Although not confirmed as evidence is hard to come by, some growers believe that the tobacco mosaic virus (TMV) affected their cannabis crop. 

The TMV virus is typically associated with tobacco crops. It causes twisted leaves, slowed growth, strange mottling symptoms in a mosaic pattern, and reduced yields. These symptoms can be limited to one or two blades or spread throughout the entire shrub. In some cases, plants are silent carriers and don’t display any signs at all.

Unfortunately, there’s no cure for TMV. Infected foliage will carry the virus forever, so your main goal should be to prevent the disease from spreading to other growth. Therefore, it’s essential to dispose of all infected shrubs and the dirt they were growing in. It’s also crucial to wash your hands between touching plants.

TMV isn’t known for killing shrubs, and there’s no evidence to suggest that it’s harmful to humans, but because the presence of this disease will reduce your harvest, you don’t want it in your cannabis garden.

18: Whiteflies

Whiteflies are common marijuana pests that live on the underside of pot leaves, chewing on them. They weaken your weed shrubs by sucking the sap out of the leaves while spreading diseases, ultimately ruining your harvest. 

Obvious evidence of an invasion by these cannabis bugs is the presence of tiny flies whenever you shake your weed plants. White powder on the underside of leaves and yellowed blades are also signs of infestation.

To eliminate these weed pests, you need to persistently treat your cannabis plants with repellent crops such as basil, spray your shrubs with potassium soap or neem oil, and strategically place yellow sticky strips.

19: White powdery mildew

White powdery mildew, aka white powdery mold (WPM), is a rapidly reproducing cannabis pest that eats away at your weed plants while ruining your buds.

This marijuana pest is easy to spot since it creates big patches of white fungal growth, but be careful when attempting to remove it as it contains an immense amount of spores, allowing it to spread throughout your whole garden quickly.

To effectively deal with this cannabis pest, spray your plants with a mixture of water and SM–90, hydrogen peroxide, baking soda, neem oil, or milk while using wet paper towels to wipe the WPM build-up off of the affected leaves gently.

Let the elimination commence

The best way to deal with cannabis pests is to deny them the opportunity to invade your crops. 

Installing floating row covers will prevent these bugs from getting to your plants, while introducing predatory insects will significantly reduce their numbers. Alternatively, you can use one of the many organic and eco-friendly products available on the market to eradicate weed pests.

Whichever method you choose to eliminate marijuana bugs is up to you, just as long as you stay away from chemical-based pesticides. These end up being more damaging than you may imagine and can even result in making your harvest unfit for humans.

It’s also wise to invest in pest and mold resilient cannabis seeds.

Our online store offers a wide selection of premium mold and pest-resilient seeds, shipped with the utmost discretion for your safety. Start your marijuana cultivation experience today and order your first batch of high-quality seeds and from i49 Genetics.