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A Natural Approach to Reducing Pesticide Use on Cannabis Plants

A Natural Approach to Reducing Pesticide Use on Cannabis Plants

A major hurdle to growing clean cannabis is pest control. When insects begin to take over a cannabis crop, cultivators have limited options outside spraying plants with pesticides. This blog discusses some of the safer alternatives growers should consider before resorting to the use of chemical or natural pesticides, as well as best practices to keep in mind if a cultivator must resort to pesticides to salvage a crop.

Growers face a unique challenge in managing pests, as lack of cannabis-specific guidelines and few examples from other industries on how to tackle the issue mean cultivators are taking risks to mitigate insects.

Some growers resort to using pesticides or insecticides to address pest issues, but inconsistent regulation and little research on cannabis pesticide use raises concerns. The use of pesticides on cannabis crops is a heavily debated issue because of this.

Let’s review the terms before diving into the debate itself. Even though people often view pesticides and insecticides as one class of chemicals, they are actually developed and used for different reasons:

Pesticide: A general term for any substance or chemical used on crops to control pests. Pesticides aim to protect plants from the development of bacteria or fungus (mold) brought on by the presence of certain insects.

Insecticide: A type of pesticide explicitly used for killing or slowing the growth of pest insects on crops.

There are currently no federal guidelines for pesticide use on cannabis, as cultivation and consumption remain prohibited under federal law. While some legal-adult-use states have created their own guidelines, they are inconsistent from state-to-state and often are issued without sufficient scientific justification.

It is unknown to what extent inhaling or ingesting pesticide residue found on cannabis products is potentially harmful. Even with the minimal peer-reviewed research published thus far, some tests show cause for significant consumer concern – particularly for patients under medical care or those with high-risk factors. A 2013 study published in the Journal of Toxicology found that smoked cannabis products can retain up to 69.5 percent of pesticide residues even after the cultivator has treated it.

To make matters worse, because most agricultural products aren’t consumed through combustion, there are not many examples from other industries to base safe use guidelines on. Even though farmers in the tobacco industry face similar challenges in growing a smokeable crop, they can rely on filters to absorb the majority of pesticide residue that may remain on their products. This solution has no application in the cannabis industry and still poses health risks to consumers.

Recently, the Environmental Protection Agency registered ten pesticide products for approved use on hemp, the first action of its kind from the federal agency. While an approved pesticide list is significant progress for the hemp industry, it is not a valid guideline for cannabis cultivation, and specific regulations for cannabis are still needed.

The Solution? A Multi-Tiered Approach to Growing Clean

Ideally, cultivators should avoid pesticide use altogether. Growers often resort to using pesticides as a response to an issue, such as an insect outbreak in a cultivation facility. Instead of using reactionary methods to address such problems, cultivators should fix the source of the problem by adopting clean growing practices.

But if a pest problem arises despite a grower’s best efforts, there are solutions for protecting plants and avoiding an outbreak without resorting to unregulated pesticides. The options:

  • Beneficial Insects

Beneficial insects, sometimes referred to as biological control agents, have become a go-to solution for many commercial grows trying to mitigate pest issues without using pesticides. There are many insects, like predatory mites, nematodes, and species like wasps and beetles, that target some of the most common cannabis pests. This method is popular because the beneficial insects do not harm cannabis plants and can be strategically released into facilities to sync with growing and harvesting schedules.

Several specialized companies, like Natural Enemies, have narrowed down the best types of beneficial insects to use and sell products that include bugs and methods for releasing them. Still, growers should own their processes by researching which kinds of insects would best serve their needs and ensure there are no concerns that a type of insect may cause further issues. It is also possible that using only one type of insect may be insufficient for addressing some pest issues, as a combination of different insects may be more effective.

While beneficial insects have become a widely accepted, safe solution to addressing pest issues, outbreaks are not as easy to control using beneficial insects. It takes more time and a larger volume of insects to combat an outbreak. Growers should strive to avoid outbreaks at all costs, as there are few options to solve the problem without resorting to pesticide use.

  • Companion Planting Pest Control

Building a dynamic ecosystem within a cannabis cultivation space can create an extra layer of defense against a variety of different pests. Lavender, basil, sage, and rosemary plants have a distinctive unattractive scent to certain pests and function as a cover crop for cannabis.

Companion planting is a suitable option for outdoor growers cultivating in larger beds, but it can also work for growers with smaller yielding harvests. Marigolds, for example, are a bright, colorful and compact companion plant that can act as a barrier between cannabis pots and pests.

  • Natural or Organic Pesticides

Natural or organic pesticides, often called biocides, are considered by some to be safe for use on cannabis plants because they are bacteria- or plant-based. But this is yet another instance where insufficient research impairs our ability to make definitive claims about product safety.

The Cannabis Horticultural Association frames it this way: “Generally speaking it is safe to assume that most organic and biological pesticides sprayed during vegetative growth will be completely safe but there is an unknown cutoff point for discontinuing spraying during flowering. It’s that cutoff point that needs to be thoroughly tested and analyzed as well.” It is clear, though, that pesticides, organic or not, should not be applied after the plant progresses past the vegetative stage.

If a grower must resort to using biocides, they should first consult their state’s specific regulations for pesticide use, which can include guidelines for organic pesticides in addition to chemical pesticides. Cultivators should also extensively research the products they intend to use and strictly follow label instructions, including proper application and storage practices. The Pesticide Action Network has information on more than 6,500 pesticides available on their website: www.pesticideinfo.org.

  • State-Approved Pesticides

If a cultivator’s only option to salvage a harvest is using pesticides, they must follow all applicable state guidelines for doing so. Like biocides, cultivators need to follow all label instructions on any pesticides used. Not following guidelines on pesticide labels is against the law.

Further, because there have been numerous cases of mislabeled pesticides coming from manufacturers, cultivators need a validation process for all pesticides they intend to use. Labels should be read multiple times, and if there is any suspicion a pesticide may have been mislabeled, growers should immediately contact the EPA pesticide hotline at 800-858-7378.

And if you’re not going to validate the pesticide yourself, only purchase from companies that provide third-party testing results with your product.

Final Best Practices

As mentioned previously, any chemical or biological efforts to rid plants of pests should not occur after the vegetation stage. If this is unavoidable, we still recommend you (a) avoid pesticides or biocides within two weeks of harvest and (b) conduct a thorough flush before harvesting.

Additionally, growers and other cultivation employees should take all necessary safety precautions when working with organic and non-organic pesticides, including always wearing personal protective equipment (masks, scrubs, gloves, shoe covers) when spraying crops. To avoid contamination, growers should also follow storage guidelines on pesticide labels.

Pesticide Remediation Options

There are some options for reducing or eliminating pesticide residue on plants after harvest, in addition to removing residual pesticides from cannabis concentrate. You can easily find the companies that offer this service by googling cannabis pesticide remediation.

And what about ozone? Even though studies show ozone gas can be an effective agent for removing pesticide residue from cannabis, we do not include this type of decontamination in our services because the full breadth of pesticides used on crops makes it challenging to guarantee effective treatment.

However, a WillowPure system does act as a reliable kill-step for the cannabis harvesting process and benefits growers trying to refine their clean growing processes and avoid risky solutions like pesticides. To implement a WillowPure system in your cultivation process, contact us today, we’d love to help.

Willow Industries - January 16, 2020