Pests in Cannabis Plants: How to Prevent Them

Any cannabis cultivation business owner can tell you that dealing with an infestation of pesky insects can be extremely taxing. While unfortunate, pests are a common problem within the industry, and they can cause many different issues. Pests in your cannabis plants kill the plant they are making a home in and these annoying critters can also increase the likelihood of plant diseases spreading. The biggest concern pests can create for cultivation operators is causing them to fail the mandatory testing. Testing is designed so that end products are contaminant-free. If an operation fails this testing, the whole product line has to be destroyed. As a cannabis grower, you may think, “I already understand the risks associated with pests.” But, the more knowledge you have about these unwanted visitors, the more easily you can identify and tackle any pest-related issues quickly.  

The easiest way to keep your cannabis operation pest-free is actually to prevent them from ever popping up in the first place. Some of the most critical factors regarding keeping your cannabis plants pest-free are your operation setup and maintenance. While preventative measures may seem annoying and overwhelming initially, your future self will be extremely thankful after your first run-in with pests. 

If you find yourself in a scenario where even though proper preventative measures have been taken and there is still a pest issue, the information below can help you: 

• Rid your greenhouse of critters
• Save your marijuana plant yield
• Save your time and money  

Laid out below is an extensive amount of information regarding:

• Common pests and insects that cannabis cultivators see
• Tips on pest and insect prevention 
• Tips on pest and insect elimination 
• And more!

Even the most formidable pests and insects are no match for a highly informed cannabis grower. 

What Are The Most Common Pests Affecting Cannabis?

The lists of pests and insects that cannabis cultivation operators experience can vary due to various factors like location, operation size, growing season, and more. While many pests could make an appearance, a few different insect species are particularly known for causing issues within marijuana cultivation operations. Some of the most likely culprits in the cannabis cultivation industry include:

1. Whiteflies: While not technically a part of the fly family, whiteflies are soft-bodied, winged insects that can quickly breed. 

2. Fungus Gnats: A common pest for many house plant owners, fungus gnats are small flies that are typically attracted to moist environments.

3. Aphids: Aphids are closely related to whiteflies and can vary in color and size. 

4. Spider Mites: Typically found on the underside of plant leaves, spider mites are extremely tiny and are known for spinning silk, like spiders. 

Each of these pesky insects is explained in further detail below. 

Whiteflies

Whiteflies are a member of the Aleyrodidae family. These pesky critters are small, with a wingspan of no more than 3 millimeters and a body size/length of 1 to 2 millimeters. Whiteflies are typically white in color, hence their nickname. The expected adult lifespan for these insects is anywhere from 30 to 40 days. Female adult whiteflies can lay many hundreds of eggs in their relatively short lifetime. 

Whiteflies are a common pest in the cannabis cultivation industry. These insects spend most of their time on the underside of cannabis leaves and can be found in subtropical regions worldwide. These bugs can harm the leaves of your cannabis plants, spread disease to plants, and weaken a cannabis plant’s overall health. 

How To Get Rid Of Whiteflies

In theory, the best way to rid your cannabis plants of whiteflies is to prune and comb through each one and ensure that no insects or eggs remain. While most effective, this method is not feasible for all growers, especially those that are conducting a commercial cannabis operation. 

One whitefly removal method that could be more attainable in a commercial operation is companion planting. Companion planting is when two or more plants are grown close together in order for one or both of them to benefit from the growing process of the other. Suppose you’re cultivating cannabis and find a whitefly infestation. You then decide to grow marigolds and zinnias nearby the cannabis plants. In that case, the marigolds and zinnias (both flowering plants that pests like whiteflies dislike) benefit your cannabis plants and drive the insects away. 

There are also many solutions you can mix with water and spray on your cannabis plants that will discourage whitefly infestations. Some of these solutions include: 

• Insecticidal Soaps: Insecticidal soaps kill insects very effectively. These soaps seem to disrupt the insect’s cellular membranes and eliminate protective waxes and secretions that coat the pests, which will eventually cause dehydration and death.

• Neem Oil: Neem oil is an organic pesticide that is created with the seeds of neem trees. Neem oil is often a yellowish brown color and has a displeasing smell.

• Spinosad: Spinosad is an organic insecticide that is made with a soil bacterium. It is typically toxic to many insects but does not harm most plants.

• Essentria IC3: Essentria IC3 is a safe pest control solution made with rosemary oil, geraniol, and peppermint oil.

Preventative Measures Against Whiteflies

Some of the many preventative measures you can take to avoid whitefly infestations in your commercial cannabis operation include:

• Enhancing Ventilation Systems
• Avoiding High Temperatures
• Decreasing Humidity 
• Increasing Facility/Grow Room Cleaning Consistency

Fungus Gnats

Fungus gnats are a member of the superfamily Sciaroidea. These little gnats are larger than whiteflies, typically measuring anywhere between 2 to 8 millimeters in size. Fungus gnats are generally black in color, and the expected adult lifespan for these insects is around a week long. Female fungus gnats can lay up to 200 tiny off-white colored eggs in their very short lifetime. 

Fungus gnats are a common pest in the cannabis cultivation industry and can be found in moist environments all over the planet. Pesky fungus gnats spend most of their time in the soil and on the base of cannabis plants. Though fungus gnats do not eat or attack cannabis plants, they can still cause damage to plant roots and plant soil. 

How To Get Rid Of Fungus Gnats

Fungus gnats are known for thriving in moist soil, so the best way to ensure they aren’t a problem for your cannabis plants is to keep the top layer of soil as dry as possible. Also, placing cloth over the top of your plant’s ground soil can keep these bugs at bay as the fabric can prevent pests like fungus gnats from laying eggs. Keeping your grow room as sealed as possible is imperative when trying to rid your operation of fungus gnats. These critters can quickly move from plant to plant and take over. 

There are also many solutions you can mix with water and spray on your cannabis plants that will discourage fungus gnat infestations, including: 

• Neem Oil: Neem oil is an organic pesticide that is created with the seeds of neem trees. Neem oil is often a yellowish brown color and has a displeasing smell.

Diatomaceous earth is another product that can help with these infestations. Diatomaceous earth is a powdery substance made from fossilized algae. Diatomaceous earth is used as an insecticide and kills insects by dehydrating them.

Preventative Measures Against Fungus Gnats

Some of the many preventative measures you can take to avoid fungus gnat infestations in your commercial cannabis operation include:

• Enhancing Ventilation Systems
• Increasing Light Levels
• Decreasing Humidity 
• Increasing Facility/Grow Room Cleaning Consistency

Aphids

Aphids are a member of the superfamily Aphidoidea. They are tiny, and while larger than whiteflies, they often measure smaller than fungus gnats. Aphids can be found anywhere between 2 to 4 millimeters in size. These pear-shaped bugs come in a wide variety of colors, including white, black, brown, gray, yellow, green, and pink. The expected adult lifespan for these insects is around one month, and adult female aphids can lay hundreds of eggs throughout their short life cycle. 

Aphids are a common pest in the cannabis cultivation industry. These critters can be found in many environments. While aphids are hearty, they tend not to enjoy extremely hot or cold locations. Aphids spend most of their time on the underside of cannabis plant leaves. While all aphids are considered pests, some are more harmful than others. Certain species of aphids can even inject toxins into plant leaves, causing them to curl and their growth to be distorted. 

How To Get Rid Of Aphids

Like with whiteflies, the best way to rid your cannabis plants of aphids is to prune and comb through each one and ensure that no insects or eggs remain. This method is highly time-consuming and taxing; thankfully, there are many other options to lean on. One popular method for ridding cannabis plants of aphids is introducing ladybugs to your operation. Aphids are a natural food source for ladybugs, so when these beneficial insects are introduced to plants with an infestation, they can quickly rid the cannabis of their aphid problem. 

There are also many solutions you can mix with water and spray on your cannabis plants that will discourage aphid infestations. Some of these solutions include: 

• Insecticidal Soaps: Insecticidal soaps kill insects very effectively. These soaps seem to disrupt the insect’s cellular membranes and eliminate protective waxes and secretions that coat the pests, which will eventually cause dehydration and death.

• Neem Oil: Neem oil is an organic pesticide that is created with the seeds of neem trees. Neem oil is often a yellowish brown color and has a displeasing smell.

• Spinosad: Spinosad is an organic insecticide that is made with a soil bacterium. It is typically toxic to many insects but does not harm most plants.

• Essentria IC3: Essentria IC3 is a safe pest control solution made with rosemary oil, geraniol, and peppermint oil.

Preventative Measures Against Aphids

Some of the many preventative measures you can take to avoid aphid infestations in your commercial cannabis operation include:

• Enhancing Ventilation Systems
• Increasing Temperatures
• Increasing Humidity 
• Increasing Facility/Grow Room Cleaning Consistency

Spider Mites

Spider mites are a member of the Tetranychidae family. These pests are the smallest of any mentioned here, often measuring less than 1 millimeter in size. Spider mites are typically either black or red in color. The expected adult lifespan for these insects is anywhere from 15 to 30 days. Spider mites can lay large numbers of nearly invisible eggs in their relatively short lifetime. 

Spider mites get their name from the silk webbing they produce. These webs are often the identifier for an infestation as the insects are tiny. Without proper plant surveillance, these pests can quickly decimate a cannabis cultivation operation without even being noticed. Spider mites are known to damage cells within plant leaves, turning them yellow. Spider mites can also stunt plant growth and even hinder the development of cannabis in the flowering stage. 

How To Get Rid Of Spider Mites

An interesting fact to note when it comes to spider mites is that, unlike most other pests, spider mites have a tendency to adapt to pesticides and chemical solutions, making those forms of treatment less effective. Finding an effective way to rid your plants of spider mites is challenging, and often it takes a medley of methods to ensure your plants are spider mite free. Many people opt to start with consistent plant sprayings with a mix of water and insecticidal soaps. 

There are many solutions you can mix with water and spray on your cannabis plants that will discourage spider mite infestations. Some of these solutions include: 

• Insecticidal Soaps: Insecticidal soaps kill insects very effectively. These soaps seem to disrupt the insect’s cellular membranes and eliminate protective waxes and secretions that coat the pests, which will eventually cause dehydration and death.

• Neem Oil: Neem oil is an organic pesticide that is created with the seeds of neem trees. Neem oil is often a yellowish brown color and has a displeasing smell.

• Spinosad: Spinosad is an organic insecticide that is made with a soil bacterium. It is typically toxic to many insects but does not harm most plants.

• Essentria IC3: Essentria IC3 is a safe pest control solution made with rosemary oil, geraniol, and peppermint oil.

Diatomaceous earth is another product that can help with these infestations. 

Preventative Measures Against Spider Mites

Some of the many preventative measures you can take to avoid spider mite infestations in your commercial cannabis operation include:

• Enhancing Ventilation Systems
• Decreasing Temperatures
• Increasing Humidity 
• Increasing Facility/Grow Room Cleaning Consistency

Additional Tips For Preventing Insects On Cannabis

Ensure Your Operation’s SOP Has Pest Prevention Guidelines

A standard operating procedure (SOP) is a type of documentation that a business owner can use to organize all aspects of their company. SOPs also help you ensure that your business practices and protocols are consistent. Cannabis cultivation SOPs serve as a guide for growers to follow when cultivating cannabis. By having a set of guidelines to follow, growers can ensure that they are producing a high-quality product, that production runs smoothly, and that they comply with federal, state, and local legislation. 

An SOP can also help with pest prevention. These documents often provide guidelines for cannabis plant growing conditions, moisture conditions, and much more. SOPs can also act as a checklist for pest prevention guidelines. With an SOP that contains pest prevention guidelines, you can ensure:

• Employees within your growing operation receive the same standardized information
• Common pest information is easily accessible 
• Rules and regulations about pesticide use are being followed
• And so much more!

Keep Your Greenhouse Consistently Clean 

Proper cleaning and sanitization practices will always help to keep pests at bay. Ensure any tools used for your commercial cannabis operation are sanitized and stored in an environment where molds and fungi pests love are not allowed to fester. 

Smooth Operations Take Time And Dedication

Any commercial cannabis grower can tell you that dealing with pests is inevitable to a certain extent. Growing marijuana plants requires a level of dedication and attention to detail that can take time to develop fully. While cultivation can seem daunting, when you have the proper knowledge and information, you can ensure your yields are large, and your operation is successful. 

Frequently Asked Questions