What is Pyrethrin and Should You Use It for Cannabis?

We’ve covered the most popular pesticides you can use for your cannabis plant, including neem oil. But, what if we tell you that you’ve skipped out on one of the most underrated organic pesticides you can use on your cannabis plant? 

We’re talking about pyrethrins. At first, you may discard them as synthetic since there are many such pesticides but don’t do so just yet. Pyrethrins can be THE pesticide you’re looking for. 

They are eco-friendly, organic, and extremely effective at killing pests. In this article, let’s dive into the world of pyrethrins and understand what makes them so awesome for cannabis plants, including their benefits and some tips on using them. 

What is Pyrethrin?

Pyrethrins are natural insecticides that are produced from some species of chrysanthemum flowers. These pesticides comprise six compounds, including pyrethrin, cinerin, and jasmolin. They possess insecticidal properties and have been historically utilized for pest control purposes.

However, they are extracted with some form of impurities in them. To get over this, manufacturers often produce synthetic versions of the same, which are called pyrethroids. But for the sake of this article, we’ll be referring to pyrethrins. For reference, you may even come across the term pyrethrum, which is a catch-all term for both pyrethrins and pyrethroids. 

Pyrethrin is sourced from plants belonging to the chrysanthemum or Tanacetum genus, scientifically known as Tanacetum cinerariifolium. It is also often called the Pyrethrum Daisy or Dalmatian chrysanthemum; the plant resembles a common dasy with white petals and a yellow center. 

Synthetic pyrethrins are artificially created chemicals engineered to imitate the structure and functions of natural pyrethrins. They are typically developed to be environmentally stable and effective against pests. They aim to amplify the characteristics found in pyrethrins. Popular pyrethroids include permethrin, cypermethrin, and deltamethrin. These chemicals are frequently altered to withstand degradation from sunlight and air thereby increasing their effectiveness over prolonged periods.

Natural pyrethrins break down rapidly when they come into contact with sunlight, oxygen, and moisture. This means they don't last long and are less likely to build up in the environment. This is where synthetic pyrethrins have an edge as they are designed to be more stable and long-lasting. They provide prolonged protection as they are stable, making them particularly valuable in situations requiring long-term pest management. However, this extended efficacy can also force the pests to develop resistance over time.

While this stability makes them effective for long, it also raises concerns about their impact on the environment and the potential for accumulating in organisms.

Regarding toxicity and safety, both natural and synthetic pyrethrins are considered low in toxicity when used correctly. However, they can still cause skin irritation, breathing problems, and allergic reactions in some individuals. Therefore, it's crucial to follow safety protocols and wear proper gear when handling these substances.

In terms of effectiveness, natural pyrethrins work well against pests like aphids, spider mites, and whiteflies that are commonly found in cannabis plants. While they are very effective indoors, their quick breakdown may limit their effectiveness outdoors.

Coming to how both types impact the environment, the quick breakdown of natural pyrethrins means they are less likely to persist in the environment and other organisms you're not targeting. They are generally seen as more friendly than their artificial counterparts.

Synthetic pyrethrins, despite being effective, can impact the environment more due to their persistence. If you don't use it responsibly, it has the potential to impact insects, aquatic life, and other non-target organisms.

While this insecticide has been in use for a long time, the same has been utilized in the US since the 1950s, and today, over 2,000 registered insecticides contain these compounds. You can purchase this in either liquid or granular forms. 

Fun fact: pyrethrins are also used in other products like head lice treatments and pet shampoos. They are also used in grain storage and poultry pens for pest control. Plus, some pyrethrin products are even suitable for organic cannabis farming. Let’s see how it works and if you can use it for cannabis in the following sections. 

How are Pyrethrins Produced? 

As mentioned above, the source of pyrethrin is the chrysanthemum plant, particularly varieties like Chrysanthemum cinerariifolium and Chrysanthemum coccineum. These flowers are usually grown in mild climates including certain parts of Africa, Australia, and the Mediterranean region. They need well-draining soil and enough sunlight, just like cannabis plants. 

And, again, just like the quality and effects of cannabis buds depend on when you harvest them, the timing of when they harvest chrysanthemum flowers is also important to get the pyrethrin from the flowers. The chrysanthemums should be picked when they are mature as that's when the pyrethrin concentration is highest.

Harvesting usually happens from summer to autumn depending on where they are grown. Farmers watch the flowering cycle closely to know when to harvest and often do so in the morning or late evening when it's cooler. This helps keep the pyrethrins intact since they can break down in heat and sunlight.

Some commercial producers have sophisticated machines that pick flowers mechanically. However, this isn't as precise as hand-picking. Mechanical harvesting can enhance efficiency and reduce labor costs, but it might compromise the quality of the harvested material. Consequently, it is not commonly utilized for pyrethrin production where quality is crucial.

Therefore, top companies employ staff that pick the flowers by hand. They choose the blooms carefully and gather only the ones that are in full bloom. Most importantly, they pick top-notch flowers. 

Interestingly, the workers are so skilled that they only pick flowers with high levels of pyrethrin to guarantee high yields. In addition, they treat the flowers gently to avoid any damage to pyrethrins and loss of yield. Sounds similar to harvesting cannabis buds gently to avoid damaging the trichomes, eh?

Next, the flowers are processed almost immediately to maintain their pyrethrin content since delays can result in the degradation of compounds. They are transported promptly to drying facilities in containers that shield them from damage and exposure to heat or moisture.   Typically they maintain a moisture content of 10-12% for great results.

Next, the flowers are stored in perfect environmental conditions until they are ready to extract pyrethrin. Companies can use two ways to dry the flowers: mechanical and natural. 

While they can dry the flowers in natural sunlight, it typically takes several days under the right conditions where there's enough ventilation. Plus, they should turn the flowers around frequently to ensure uniform drying and prevent mold. Although this method reduces costs to an extent, most companies rely on mechanical processes to eliminate the guessing game. 

Mechanical processes use precise heat and airflow and monitor the flowers to ensure the flowers are in pristine condition. Like drying cannabis buds, they use dehydrators and dryers so that the flowers yield more pyrethrin. 

Once they are dry, the flowers are finely ground to aid in the extraction process. For this, the powder must be turned into liquid, which can be done using alcohol or hexane. These solvents can help extract pyrethrins from the powder, separating them from plant matter. Then, the mixture is filtered and purified to remove the impurities. 

Subsequently, the solvent is evaporated, resulting in a pyrethrin concentrate. Further refinement can be done to enhance its purity. Sometimes, some manufacturers also add other ingredients to the liquid to make it more potent. For example, they may add carriers or stabilizers to improve the pesticides’ stability and ease of application. 

Now, you know a lot about how natural pyrethrins are produced. But, considering the rising demand and challenges associated with natural extraction processes, manufacturers develop synthetic pyrethrins (pyrethroids). These synthetic compounds share similarities with natural pyrethrins but are more stable as you know already. This process involves complex techniques revolving around organic chemistry to produce molecules that imitate the structure and insecticidal characteristics of natural pyrethrins.

However, regardless of whether it's natural or synthetic, they both undergo lots of testing to ensure they adhere to safety and effectiveness standards, including assessments for purity, potency, and absence of impurities. Production facilities must adhere to guidelines established by environmental authorities to confirm the product's safety. 

Next, pyrethrin extracts are incorporated into various formulations to produce several products that can be used as dust, sprays, and foggers. They are labeled and then shipped to stores where you can purchase them to get rid of some of the most nasty creatures that affect your precious cannabis plants. 

How Do Pyrethrins Work?

Pyrethrins are excellent insecticides. They work by targeting insects; they overstimulate their nervous system, leading to paralysis and death. When pests come in contact with them, they become immobilized within minutes. 

Manufacturers also add synergists to their pyrethrin products to make them even more potent and boost their insecticidal properties. These synergists help delay the detoxifying enzymes in pests, ensuring a more lethal application. One common synergist is piperonyl butoxide. 

In other words, pyrethrins are incredibly effective at getting rid of common cannabis pests, including aphids, thrips, fungus gnats, white flies, spider mites, caterpillars, mealybugs, and more. 

Let’s take a detailed look at just how pyrethrins work:

Mechanism of Action

Pyrethrin acts by targeting the pest’s nervous system causing paralysis and eventual death. The process involves a few stages:

1. Neural Disruption: Pyrethrin impacts the sodium channels in an insect’s nerve cells which are vital for generating and transmitting electrical signals in the nervous system. By binding to these channels, pyrethrin hinders them from closing after an electrical signal passes through.
2. Continuous Nerve Firing: With the sodium channels staying open, the nerve cells that are affected experience uncontrolled firing. The excessive excitement leads to a lack of coordination, muscle spasms, and eventually paralysis.
3. Knockdown Effect: When insects are exposed to pyrethrin, they experience something known as a “knockdown effect" which causes them to become immobilized swiftly. This quick response is particularly effective in managing moving or flying pests.
4. Fatality: Prolonged contact with pyrethrin results in paralysis, ultimately leading to the insect's demise. In some instances, the insect may recover if the exposure is insufficient to maintain paralysis until death.

If you’re growing cannabis and are looking for an effective pesticide to get rid of pests, pyrethrins may be your best bet. 

What are the Benefits of Using Pyrethrins on Cannabis?

Pyrethrins offer various benefits as a pesticide for cannabis. It is highly efficient against a wide range of pests making it a popular option for household pest control, especially due to its effectiveness and environmental compatibility. 

These benefits also make it an organic solution (if you’re using natural pyrethrin) to fight against pests. Depending on the formulation, it can be as organic as neem oil but even more effective at getting rid of pests. But, you do need to be wary of what other compounds the manufacturer may have used during the production, though. 

Its efficacy stems from factors such as:

• Broad spectrum activity: Pyrethrin can combat pests such as aphids, spider mites, whiteflies, beetles, caterpillars, and more. They are extremely capable of killing insects on contact. This makes them an excellent solution for immediate pest control. In addition, their extensive range of activity makes them adaptable for use in various settings. 
• Quick action: The rapid knockdown effect of pyrethrin is one of its strengths. This immediate impact is crucial for managing pests that can rapidly propagate or cause harm within a short period. Fortunately, you don’t have to worry about them damaging the local ecosystem around your cannabis garden. 
• Does not leave too many residues: While pyrethrin is powerful, it breaks down rapidly when exposed to sunlight, air, and moisture. This quality means that it does not linger in the environment too much, reducing the chance of prolonged exposure and accumulation. However, this also implies that multiple applications might be needed to effectively manage pests over time.
• Minimal pest resistance: Pests don't develop too much resistance to natural pyrethrins compared to other insecticides, as they degrade pretty quickly. 
• Suitability for Integrated Pest Management (IPM): Pyrethrins’ fast breakdown rate and efficacy make it great to combine with other pest control methods to improve strategies without majorly impacting beneficial insect populations.
• Flexibility in applications: Pyrethrin can be utilized in many types of formulations such as sprays, dusting, and foggers. This flexibility allows you to apply it based on the type of pest you're dealing with. 
• Organic growing compatibility: Many insecticides and pesticides cannot be combined with organic ones as they won't work. However, you can use natural pyrethrins even with organic cannabis farming. If you're growing commercially, it aligns with cultivation standards and can be incorporated into pest management strategies.
• Safe for humans and pets: If you use it as directed on the label, pyrethrin poses minimal risk to humans and pets. This makes it a safer alternative for both growers and consumers compared to other pesticides.

Drawbacks of Using Pyrethrin in Cannabis Cultivation

• Frequent applications needed: Pyrethrin breaks down quickly when exposed to sunlight, air, and moisture. Although we mentioned this as an advantage, its short-lived effectiveness demands many reapplications to eliminate the pests. In commercial setups with a large amount of plants, this can be quite labor-intensive and demand more staff. This can sometimes be a burden even for home gardeners with limited resources. 
• Short-term pest control: Adding to the previous point, pyrethrin’s nature of degrading quickly may not offer prolonged protection against pests. This could pose challenges in environments that are prone to pest issues or severe infestations.
• Can cause harm to other beneficial insects: Although natural pyrethrins are typically safe, synthetic ones can affect other beneficial organisms and aquatic life as well. Improper use can lead to water contamination through runoff creating risks.
• Safety concerns for humans and pets: Yes, we mentioned that it’s safe but it all depends on how you use it. Improper use or using it too much can still trigger skin irritation, respiratory problems, and allergic reactions in some individuals. Proper precautions and protective measures are crucial in reducing these risks. We will cover this in detail in the coming sections. 
• Challenges in application: For pyrethrin to work effectively, you must use it at a specific time and also under specific conditions. For example, it's most effective when you apply it in the morning or late in the evening when the temperatures are lower and beneficial insects are less active. Although most pesticides have this condition, it can be problematic for some growers who can't tend to their plants at such times. 
• Legal challenges: Regulations concerning the use of pyrethrin on crops and cannabis vary across regions. If you're a commercial producer, you should stay updated on such regulations and ensure compliance to avoid legal consequences. Violating these regulations can lead to fines. If it's banned in your state or country, it will anyway be very difficult to procure it, so it’s tough for even home gardeners to use it. 

Methods of Application

You can use pyrethrin in various ways. Let’s take a detailed look at them so you choose the one that suits you. 

Foliar Sprays

To apply foliar sprays, you need to mix the pyrethrin concentrate with water as per the manufacturer's instructions and spray it directly onto the leaves and stems of cannabis plants using a sprayer. Ensure that the spray covers all parts of the plant including the sides of leaves where pests tend to hide.

Advantages: This method allows sufficient contact between pyrethrin and pests leading to the knockdown effect. It works well for dealing with insects like aphids, spider mites, and whiteflies that are found on cannabis plants. 

It is best to spray during the early morning or late evening to reduce plant stress and prevent leaf burn. However, wear protective gear including safety goggles and a full-arm shirt to avoid exposure and be careful not to let the spray drift onto other plants or beneficial insects.

Fogging

Fogging entails using a fogger to spread pyrethrin as a mist throughout the growing area. This mist can reach pests in hidden spots within the foliage.

Advantages: Fogging is highly effective for treating outdoor areas and indoor grow spaces where pests may have hidden in small crevices or under leaves. The fine mist ensures that the insecticide is evenly spread out.

Using this method requires equipment, though. In addition, wear a mask so you don't inhale the mist. Make sure there are no pets in the area until you finish fogging. Also, leave the treated area until the mist settles and it's safe to return.

Soil Drenching

Soil drenching involves mixing pyrethrin with water and applying it around the base of cannabis plants. This targets pests living in the soil like fungus gnats, root aphids, and larvae.

Advantages: This method directly delivers pyrethrin to soil pests that aren't affected by sprays or fogging. It's also best for pests that love attacking the roots of the plants. However, be cautious not to saturate the soil which can harm roots. Follow dosage and application frequency guidelines closely to avoid plant damage. 

Dusting

Pyrethrin is also available in dust form and you can apply it by lightly dusting the leaves and stems. Using a duster or sprinkler to spread the pyrethrin powder is one way to go about it.

Advantages: Dusting comes in handy when you can't use other applications. For example, the climate could be very humid so foliar sprays may not be the best option. Also, liquids don’t dry easily in such conditions, so dusting could be a better idea. 

Be careful while dusting and you also should avoid inhaling it and prevent it from drifting to other areas. It's not commonly used because there's a high chance of applying it unevenly. 

Dosage and Frequency

So, how much pyrethrin is too much? What’s the concentration? Read on…

The dosage varies depending on the formulation and product. This is why it's best to follow the manufacturer's instructions on the label, which is crucial for mixing ratios that ensure safety and efficacy. 

Pyrethrin generally works well at concentrations between 0.1% and 1%. This range offers flexibility based on how the pests develop resistance and your plant’s requirements. Use measuring tools to mix the specific amount of pyrethrin concentrate with water. Proper blending ensures even distribution and maximum effectiveness.

However, remember that going beyond the recommended amount can result in phytotoxicity and harm your plants. It also raises the chances of harming beneficial insects.

Frequency

You can use pyrethrin as a preventive measure every 7 to 10 days. This consistent routine helps in maintaining pest populations at minimal levels and prevents outbreaks.

In cases of an uncontrollable infestation, frequent applications might be needed. Depending on the severity, pyrethrin can be applied every 3 to 5 days until the infestation is managed.

After you apply pyrethrin, regular monitoring of pest populations and plant health is essential. Adjust the application frequency based on how effective it is. 

Again, remember that If the manufacturer's guidelines say that it's best to use it once every 3-5 days, you should follow that rule. Overusing it will make the pests develop resistance very quickly and also harm the plants. 

Can You Make Pyrethrins at Home?

Protecting your cannabis plant from pests is one of the most important factors of a healthy cannabis garden, but it is also important that you avoid synthetic pesticides that may be harmful to the environment. 

So, if you’re looking for something organic, pyrethrin is an excellent choice due to its natural origins and effectiveness. Fortunately, it is also quite popular and readily available in horticultural stores if it’s not restricted for use. 

You can even find products that contain not only pyrethrin but also other compounds like neem oil, insecticidal soap, and fatty acids. These additions further increase the effectiveness of the pesticide against pests while being organic. 

If you’re wondering if you can make it at home — yes, you can. However, the process is a bit complicated and not always worth it. It’s better to buy it from a store; it saves you a lot of time and effort. 

Nonetheless, if you want to go the DIY route, you can use dried chrysanthemum flowers, which already contain pyrethrins. Crush the dried flowers into powder and sprinkle them around your garden. 

You can even mix the powder into water and use it as foliar spray. You don’t necessarily have to extract the pyrethrins unless you’re getting rid of the impurities. It will stain and be a bit impure, though. 

Is Pyrethrin Safe?

We’ve already established that natural pyrethrin is organic, but is it safe for you and your garden (and perhaps your pets)? Let’s find out. 

For humans, pyrethrins have low toxicity levels. However, some people can experience skin irritation, tingling, or numbness due to it. It can also lead to irritation, tearing, or blurred vision if it gets in your eyes. And inhaling it may cause a runny nose, coughing, or irritation. In addition, dogs and cats are more susceptible to the effects of pyrethrin exposure and may suffer negative consequences as a result. Thus, keep your pets away from treated areas until they're safe to prevent any potential health risks.

It all depends on your sensitivity to it, but generally, most people are safe from it. Remember, it is used in lice and pet shampoos! It’s still recommended that you use it in a well-ventilated area and wear gloves to avoid direct skin contact. 

Pyrethrins are also non-toxic for birds, but they can be super toxic for honey bees. So, you must use them with caution. The same can also be risky for aquatic life, especially in cooler temperatures; long exposure affects fish reproduction. 

Environmental Impact

When it comes to the general environment, pyrethrins are pretty safe. They break down quickly in sunlight, with a half-life of around 12 hours in water and 13 hours in soil. On leaves, less than 3% of them remain after five days and they do not move readily within plants. 

However, if sunlight is absent, they may degrade more slowly, with a reported half-life of over two weeks in water. They are also less prone to breakdown in acidic water and tend to bind to sediments, with a half-life of 10 to 86 days. 

In soil, pyrethrins adhere well and have a low potential for groundwater contamination. They are typically found only in the top 15 centimeters of soil and are quickly degraded by microbes, with soil half-lives of 2.2 to 9.5 days. Pyrethrins also have a low potential for becoming airborne. 

So, while pyrethrins are effective and generally safe for humans and many mammals, they can irritate and have significant environmental impacts, particularly on aquatic life and beneficial insects like honey bees. Proper use and application are essential to minimize these risks.

Summary: What is Pyrethrin and Should You Use It for Cannabis?

That’s it. Pyrethrum is derived from the chrysanthemum flowers and is completely organic. Just make sure you purchase the right product that does not have any synthetic additions. You can even make it at home, although it won’t be nearly as effective as the commercial ones. 

This is your shot at killing pests in your cannabis plant instantly. This pesticide causes paralysis and death in insects upon contact. Awesome, isn’t it?

Although, be careful while using it. It is pretty indiscriminate and may even kill beneficial insects in your garden. So, use it conservatively and be more targeted with your sprays. 

Finally, wear gloves and keep the pesticides away from your children and pets for safety. It is generally safe for mammals, but those who are sensitive to it may experience irritation of some sort. 

So, what are you waiting for? It’s time to start using pyrethrin in your cannabis garden and get rid of those pesky bugs that are chewing away at your plant.