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Cannabis Pests: a complete guide to management

Lucy Starley
December 4, 2023
15 min read
Mealybugs on the underside of a cannabis leaf in an indoor grow setup
Mealybugs on the underside of a cannabis leaf in an indoor grow setup
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Cannabis cultivation can be an enriching and rewarding experience, but as you may have discovered it’s not without its challenges. One of the biggest issues is dealing with pests that can damage or even destroy your plants. From spider mites to thrips, cannabis pests can quickly wreak havoc on your grow. That’s why it’s important to have a good understanding of the types of pests that commonly affect cannabis plants and how to control them. Arm yourself with knowledge and don’t let those pests win!

In this post, we’ll cover everything you need to know about cannabis pests. We’ll start by going over the most common pests that affect cannabis plants and the damage they can cause. We’ll then discuss the importance of prevention and how to implement best practices to reduce the risk of pests in your grow. Next, we’ll explore both organic and chemical pest control methods, including the benefits and risks of each. We’ll also dive into integrated pest management (IPM) and how it can be used to manage pests in a safe and effective way. Finally, we’ll discuss specific treatment options for each type of pest and the importance of proper timing and dosage.

Whether you’re a seasoned grower or just starting out, this post will provide you with valuable information and resources to help you identify, prevent, and control pests in your grow room.

Disclaimer: Any information given on this site is for educational purposes only. Please ensure if you’re growing cannabis you’re doing so in accordance with the law and subject to appropriate permissions and licences of the applicable country.

Brief overview of cannabis pests

Cannabis plants are susceptible to a range of pests that can damage their leaves, stems, and buds. These pests can include spider mites, thrips, aphids, whiteflies, and more. Some cannabis pests feed on the sap of the plant, while others chew on its leaves and buds. In addition to causing direct damage, cannabis pests can also introduce diseases to your plants, further reducing their health and yield.

So basically- Cannabis pests are your enemy and you’ll want to do everything you can to deter pests from entering your grow space! Fear not, there are lots of simple actions you can take to protect your plants. So let’s get to it…

Importance of identifying and controlling cannabis pests

Cannabis pest identification and control is essential for a successful and healthy grow. If left unchecked, pests can rapidly multiply and cause significant damage to your plants, resulting in stunted growth, reduced yield, and even death. Pests can also introduce diseases to your plants, making them more susceptible to other issues like mould and mildew.

By identifying and implementing cannabis pest control early, you can prevent these issues and ensure a healthy, thriving crop.

Overview of common cannabis pests

Barnacles cannabis pests

Barnacles- Also known as wax scales, these pests have an appearance similar to seaside barnacles. They work similarly to aphids by covering your plants in a sticky residue called honeydew.

Mealy bugs on the underside of cannabis leaf

MealybugsMealybugs are small oval-shaped pests known for producing a white waxy cotton-like web to protect themselves from heat and moisture loss- and therefore death! Mealybugs function by sucking the sap out of the leaves and stems of cannabis plants.

Spider mites underneath cannabis leaf

Spider mites – These tiny pests are some of the most common and destructive pests that affect cannabis plants. They feed on the sap of the plant, causing yellowing, stunted growth, and eventual death.

Grasshopper cannabis pest

Grasshoppers- Grasshoppers are insects that are characterised by their long hind legs, powerful jumping ability, and chewing mouthparts. They can cause extensive damage to cannabis plants by feeding on leaves, stems, and flowers, which can result in reduced yield and even plant death in severe cases.

Cricket cannabis pest

Crickets- Crickets are small to medium-sized insects that belong to the same family as grasshoppers and katydids. They can cause damage to cannabis plants by feeding on leaves, stems, and roots, and can also transmit diseases and viruses.

Damage caused by leaf miner cannabis pest

Leaf miners- Rather than insects these are actually larvae that live inside the leaves of cannabis plants. The damage they cause is very visible as they leave white trails all over the leaves of your plants.

Thrips cannabis pest

Thrips – Thrips are small, slender insects that feed on the leaves and buds of cannabis plants. They can cause discolouration, distortion, and deformation of leaves, as well as reduce yield.

Magnified cluster of aphids on a plant stem

Aphids – These soft-bodied insects feed on the sap of the plant and reproduce quickly. They can cause leaves to curl, yellow, or wilt, and can also spread diseases to the plant.

White flies cannabis pest

Whiteflies – Whiteflies are small, winged insects that feed on the sap of the plant. They can cause yellowing, stunted growth, and deformity of leaves and can also spread diseases.

Fungus gnat cannabis pest

Fungus gnats – These small, black flies lay their eggs in the soil and feed on the roots of the plant. They can cause damage to the root system, leading to reduced growth and yield.

Caterpillar cannabis pest

Caterpillars – These larval-stage moths feed on the leaves and buds of cannabis plants. They can cause significant damage to parts of the plant, including holes in leaves and buds, which can reduce yield and quality.

Macro image of a russet mite

Russet mites– Russet mites are tiny, almost microscopic pests that are frequently tough to find. They are coloured brownish-red and have an oval, slightly rounded form. If left untreated, they might result in leaf yellowing and necrosis, which can lower yields or perhaps result in crop loss altogether.

Broad mites cannabis pest

Broad mites – These tiny mites can cause significant damage to cannabis plants by sucking on the sap of the plant. They can cause leaf curling, stunted growth, and reduced yield.

Plant hopper cannabis pest

Plant hoppers- These small winged insects are known for creating a white mould-like substance on your plant. Much like mealybugs they also suck the sap out of your plant’s leaves and stems.

By being able to identify these common grow room bugs and understand their effects on your plants, you can take proactive steps to prevent and control their populations before they cause serious problems in your grow room. Remember knowledge is key in the fight against pests.

Identification of cannabis pests

To stay on top of any potential cannabis pest infestations you will need to know what to look out for. By being able to recognise the signs of cannabis pest infestations, you can take swift action to prevent further damage. Here are some common signs to look for when identifying cannabis pests:

Visible pests – Some pests, such as thrips and aphids, may be visible on the surface of the plant. However other pests are so minute that spotting them with the naked eye is much harder. A magnifying glass can be your best friend here!

Leaf damage – Many pests will cause damage to the leaves of cannabis plants, including yellowing, curling, and holes.

Sticky residue – Some pests, such as aphids and whiteflies, secrete a sticky residue called honeydew as they feed on the plant. This residue can attract other pests and cause mould growth.

Webbing – Spider mites and other pests may create webbing on the leaves and buds of cannabis plants.

Discolouration – Pests can cause leaves and buds to discolour, often turning them yellow or brown.

Root damage – Pests such as fungus gnats and root aphids feed on the roots of cannabis plants and can cause significant damage to the plant’s root system, leading to stunted growth and reduced yield.

Bud damage – Pests that feed on the buds of cannabis plants can cause them to become deformed or malformed, which can reduce their quality and potency.

Disease transmission – Some pests can also spread diseases to cannabis plants, which can cause a range of symptoms, including wilting, yellowing, and death.

Reduced yield – Pests can significantly reduce the yield of cannabis plants by damaging leaves, buds, and the root system. This can result in lower quality and quantity of harvested buds.

It’s essential to identify and control pests early to minimise the damage they cause. Implementing pest control measures like integrated pest management (IPM) can help you to prevent pests from infesting your plants and reduce the damage caused.

It’s likely that you will need to try several pest control strategies before finding which ones are most effective depending on the pest and your unique growing conditions. It takes time and effort, but this process ensures that your cannabis plants remain healthy and productive throughout the growing season.

Prevention of cannabis pests

Importance of prevention

Preventing cannabis pests from infesting your plants in the first place is essential for maintaining healthy and productive crops. Here are some reasons why pest prevention is so important for your plants:

Reduced damage

Prevention is often the most effective way to control pests since it eliminates the need for costly and time-consuming pest control measures once the infestation has occurred. By preventing pests from entering your growing area, you can minimise the damage caused to the plants and the resulting reduction in yield and quality.

Lower costs

Implementing preventative measures can be less expensive than treating a pest infestation. The cost of pest control measures like pesticides, fungicides, and other treatments can add up quickly, especially if multiple treatments are required.

Improved quality

Pest-damaged plants are not going to produce high-quality harvests if they produce anything at all. So preventing pest infestations is key to gaining a strong and healthy harvest.

Compliance with regulations

Many countries and states have strict regulations regarding the use of pesticides and other pest control measures in cannabis cultivation. Implementing preventative measures can help you to comply with these regulations and avoid costly fines and legal issues.

By prioritising prevention and implementing effective pest control measures, you can maintain healthy, productive crops and avoid the many problems associated with pest infestations. This is the goal right!?

Best practices for prevention

Maintaining cleanliness

Keeping a clean and sterile growing environment is essential for preventing pests from infesting your cannabis plants. This includes regularly removing any plant debris, maintaining a strict sanitation routine, and keeping your growing area free of clutter.

Regular monitoring of plants

Regularly inspecting plants for signs of pest damage or infestation is essential for early detection and control. By monitoring plants regularly, you can catch pest infestations early and prevent them from causing significant damage to your plants.

Proper ventilation and airflow

Good airflow and proper ventilation can help prevent the buildup of moisture, which can attract pests like fungus gnats. You can achieve this by installing fans or using air conditioning systems to maintain proper temperature and humidity levels in your grow room.

Use of natural pest deterrents

Using natural pest deterrents like neem oil, garlic, and essential oils can be an effective way to prevent pests from infesting cannabis plants. These natural remedies are less harmful to the plants and the environment than chemical pesticides and can be an excellent addition to an integrated pest management (IPM) strategy. It’s essential to know when to use these strategies though, as some natural deterrents can alter the taste of your harvest if they are used during the flowering and bud stages. You don’t want to create an unintended problem whilst trying to tackle another!

Maintaining optimum vapour pressure deficit

Maintaining the proper vapour pressure deficit (VPD) is crucial in preventing pest infestations in your grow room.

VPD is the difference between the amount of moisture in the air and the maximum amount of moisture the air can hold at a given temperature. When the VPD is too low, the air is too humid, which can create an ideal environment for pests like thrips, and fungus gnats to thrive. On the other hand, when the VPD is too high, the air is too dry, which can stress the plants and make them more susceptible to pest infestations.

By keeping the VPD within the appropriate range for the growth stage of the plants, you can help to prevent pest infestations and ensure healthy plant development.

Additionally, proper ventilation and air circulation can help to maintain the appropriate VPD, while also helping to prevent the buildup of humidity and heat, which can further reduce the risk of pest infestations.

By implementing these best practices for prevention, you can significantly reduce the risk of pest infestations and keep your crops healthy and productive. It’s essential to remember that prevention is key to effective pest control and that a combination of preventative measures and early detection can keep cannabis plants free of pests.

Using Grow Sensor to aid pest prevention

The grow sensor hanging in front of the grow app on he iPhone

Remember when we said that knowledge is key for pest prevention? Well, a great way to gain detailed and accurate knowledge about your grow room is by arming yourself with a right-hand man/woman, in the form of a smart grow room sensor such as Grow Sensor.

With any sort of growing, but particularly indoor growing, there are so many variables to monitor and manage that keeping track of it all can be a challenge. Grow sensor will take care of this headache for you. Through constant monitoring of a range of variables, Grow sensor will provide you with a dialled-in view of your grow room with live and accurate data.

This personalised data will allow you to make informed and intelligent decisions about which precautions or treatment methods to take, should you encounter a pest problem.

Organic pest control methods

Benefits of organic pest control

Organic pest control methods are becoming increasingly popular in the cannabis industry, as we seek to avoid using harmful chemicals and toxins that can harm the environment, plants and ourselves. Here are some of the benefits of using organic pest control methods:

Reduced environmental impact -Organic pest control methods use natural substances that are less harmful to the environment than synthetic chemicals. They also minimise the risk of contaminating soil and water sources with toxic pesticides.

Healthier plants – Organic pest control methods are less likely to harm your plants, which can lead to healthier and more productive crops. By using natural substances like neem oil, garlic, and essential oils, you can prevent pests without risking damage to your plants.

Safer for humans – Organic pest control methods are generally safer for us than synthetic chemicals, as they do not produce harmful fumes or residues. This is especially important for those of you who work in the growing area and may be exposed to pest control substances. Always keep yourself safe- without you, your plants really will be lost!

Some common organic pest control methods include using beneficial insects like ladybugs and predatory mites, using natural pest deterrents like neem oil and essential oils, and implementing IPM strategies that incorporate organic methods.

Examples of natural pest control methods

Yellow glue sticky trap for harmful plant insect

Neem oil

Neem oil is a popular natural pesticide that is derived from the seeds of the neem tree. It is effective against a wide range of pests, including spider mites, whiteflies, and aphids. Neem oil works by disrupting the pest’s feeding and breeding cycles and can be applied to cannabis plants as a foliar spray.

Diatomaceous earth

Diatomaceous earth is a fine, powdery substance that is made from the fossilised remains of diatoms. It is a natural pesticide that works by dehydrating insects and disrupting their exoskeletons. Diatomaceous earth is effective against a wide range of pests, including ants, aphids, and spider mites, and can be applied to the soil or dusted onto the leaves of cannabis plants.

Insecticidal soap

Insecticidal soap is a natural pesticide that is made from fatty acids and works by suffocating pests. It is effective against a range of soft-bodied insects, including spider mites and aphids, and can be sprayed directly onto the leaves of cannabis plants. Insecticidal soap is generally safe for plants, but you should avoid applying it during the heat of the day to prevent plant damage.

Beneficial insects

Beneficial insects like ladybugs, lacewings, and predatory mites can be used to control pest populations in cannabis crops. These insects prey on pests like aphids and spider mites and can be released directly into the growing area. Beneficial insects are a natural and effective way to control pest populations and can be used as part of an integrated pest management strategy.

By incorporating natural pest control methods like neem oil, diatomaceous earth, insecticidal soap, and beneficial insects into your pest control strategies, you can help maintain healthy and productive crops while minimising the risks associated with chemical pesticides.

However, remember that it’s vital that you don’t use neem oil, diatomaceous earth or insecticidal soaps during the flowering stage or on the buds of your plants as these can affect the taste and quality of your harvest. Nobody wants that!

Chemical pest control methods

largescale treatment of mealy bugs in a greenhouse

Overview of chemical pest control

Chemical pesticides are widely used in agriculture, including in the production of cannabis. These pesticides work by targeting specific pests and disrupting their life cycles or by poisoning them. Chemical pesticides can be effective in controlling pest populations, but they also carry a number of risks and drawbacks.

In recent years, there has been growing concern about the use of chemical pesticides in cannabis production, particularly in the legal cannabis industry. Many states and countries have established regulations around pesticide use in cannabis, and some have banned the use of certain pesticides altogether.

While chemical pesticides can be effective in controlling pests, they are not always the best option. In some cases, natural pest control methods like beneficial insects and organic pesticides may be safer and more sustainable alternatives. Additionally, implementing good cultivation practices like proper sanitation, plant maintenance, and pest monitoring can go a long way in preventing pest infestations in the first place.

Risks associated with chemical pest control

One of the main risks associated with chemical pesticides is their potential impact on human health and the environment. Some pesticides can be toxic and may have long-term effects on the health of people who are exposed to them. Additionally, chemical pesticides can have negative impacts on non-target species like beneficial insects, birds, and other wildlife.

Exposure to chemical pesticides can occur through inhalation, skin contact, or ingestion. Pesticides can also accumulate in soil and water, posing risks to the environment and potentially contaminating food sources.

Safety precautions when using chemicals

When using chemical pesticides in cannabis production, it is important to follow appropriate safety precautions to minimise the risks associated with exposure. These may include:

  1. Wear protective clothing and equipment, such as gloves, goggles, and respirators.
  2. Avoid direct skin contact with pesticides.
  3. Following instructions carefully and using pesticides only as directed.
  4. Properly storing and disposing of pesticides to prevent contamination.
  5. Implementing integrated pest management strategies that minimise the need for chemical pesticides.

By following these safety precautions, you can reduce the risks associated with chemical pest control and promote safer and more sustainable cannabis production practices.

Integrated pest management

Overview of Integrated pest management

Integrated pest management (IPM) is a holistic approach to pest control that emphasises prevention and the use of multiple strategies to manage pest populations. IPM strategies include cultivation, biological, and chemical methods, with a focus on using the least toxic methods first.

The goal of IPM is to manage pest populations while minimising risks to human health and the environment. By implementing a range of strategies, you can reduce your reliance on chemical pesticides.

The key components of an IPM program include

  1. Identification and monitoring of pests and beneficial insects.
  2. Implementing good cultivation practices, such as proper sanitation and plant maintenance, to prevent pest infestations.
  3. Using natural pest control methods like beneficial insects and organic pesticides.
  4. Using chemical pesticides only when necessary and following appropriate safety precautions.
  5. Regularly evaluate the effectiveness of pest control measures and adjust strategies as needed.

By adopting an IPM approach, you can reduce the risks associated with chemical pest control and maintain a grow space that is healthy and safe for all.

Benefits of integrated pest management

The benefits of IPM include:

Reduced reliance on chemical pesticides: By using a range of pest control strategies, you can reduce the need for chemical pesticides and minimise the risks associated with their use. Just remember chemicals should be your last resort.

Better pest control: IPM allows you to manage pest populations more effectively by using multiple strategies to target pests at different stages of their life cycles.

Improved plant health: By preventing and managing pest infestations, you can promote healthier plants and higher yields.

More sustainable practices: IPM promotes sustainable practices by reducing the environmental impacts of pesticide use and promoting safer, more natural pest control methods.

Steps involved in integrated pest management

The steps involved in implementing an IPM program may vary depending on the specific needs of a cannabis production operation, but generally include the following:

Identification and monitoring of pests: Regular monitoring of your plants is essential to identify pest infestations and track pest populations over time.

Biological control: The use of beneficial insects and other natural enemies can help control pest populations without the need for chemical pesticides. Using beneficial and companion plants can also keep pests at bay.

Organic pesticides: If necessary, organic pesticides can be used to manage pest populations.

Chemical pesticides: Chemical pesticides should be used only as a last resort and only when necessary. When using chemical pesticides, it is important to follow appropriate safety precautions.

Evaluation: Regular evaluation of pest control measures is essential to determine their effectiveness and make adjustments as needed.

By following these steps, you can implement an effective IPM program that promotes sustainable and effective pest control practices.

Treating cannabis pests

Specific treatments for each type of pest

For each type of pest, there are specific treatments that are most effective. Some common cannabis pests and their treatment options include:

Please note that these treatment options are not exhaustive and other options may also be effective depending on the severity of the infestation and the specific conditions of the grow operation. It’s important to carefully research and choose the appropriate treatment method for each specific situation.

Importance of proper timing and dosage

Proper timing and dosage are critical for effective pest control in cannabis production. Treatment should be done at the appropriate stage of the pest’s life cycle, and at the recommended dosage to avoid resistance development and minimise any potential harm to plants or beneficial insects. It’s also critical to apply treatments at the right growth stage of your plants. For example, pest control during flowering will differ from what is suitable during the vegetative stage.

In addition, it’s essential to monitor for pests regularly and to treat them early to prevent infestations from getting out of control. Proper record-keeping can help you to track the effectiveness of different treatment options and make adjustments as needed.

By staying informed about the latest research and best practices for pest control, you can manage pest populations effectively while minimising risks to human health and the environment.

Conclusion

Recap of key points

In this article, you learned the different types of pests that can affect cannabis production, as well as the importance of identifying and controlling pests. We discussed the damage caused by pests and the best practices for prevention, including maintaining cleanliness, regular monitoring of plants, proper ventilation and airflow, and using natural pest deterrents.

We also learned about the benefits and risks associated with organic and chemical pest control methods, as well as the importance of integrated pest management. Finally, we discussed the steps involved in implementing an effective IPM program.

Final thoughts

Effective pest control is essential for sustainable and profitable cannabis production. By adopting a holistic approach that emphasises prevention and the use of multiple strategies, you can manage pest populations while minimising risks to human health and the environment.

As a cannabis grower, it’s important to prioritise pest control in your operation. Take the time to implement an effective IPM program that incorporates a range of pest control strategies, and regularly evaluate and adjust your approach as needed.

By following best practices for pest prevention and control, you can promote healthier plants, higher yields, and more sustainable practices for the future of the cannabis industry.


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Lucy Starley
December 4, 2023
15 min read

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