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The Wild West of Cannabis Pesticides


Cultivators have multiple options for effective pest controls.

The Cannabis industry has come out of the shadows over the past few years, but pesticides are still a top challenge in the cultivation process. Pesticides for other crops have been regulated for decades, but since marijuana is still not federally legal, regulatory guidance on pesticides has yet to be provided for this booming cash crop. 

John Chandler, vice president of cultivation technologies at urban-gro, joined industry experts Jordan Wellington, Esq., director of compliance at Vicente Sederberg LLC, and Cynthia Ludwig, director of technical services at AOCS, at the Cannabis Business Summit and Expo in Oakland, Calif., in June, to discuss “The Wild West of Pesticides” in Cannabis cultivation. The experts shared their insight on how to prevent the pesticides from destroying Cannabis crops.

Using Biology for Pest Prevention

Many cannabis growers have turned to integrated pest management because it is the safest way to protect Cannabis crops. “Integrated Pest Management is the big picture. That’s what growers should be using instead of simply relying on pesticides,” Chandler said. 

Chandler advocated biological controls as the first line of defense in pest management. Biological controls, also known as biocontrols, are living organisms that are used as a method of controlling pests. “All beneficial mites and all sorts of beneficial species that you release into your garden will kill pests naturally,” Chandler explained. The types of pests that biocontrols can treat include insects, mites, and plant diseases. These biocontrols are reliant on a human management role for predation, parasitism, competition, and other natural mechanisms. He suggests predator mites such as californicus, swirskii and andersoni. 

Controlling Pests Through Climate Management 

Cultural Integrated Pest Management – or managing the climate by creating uniform airflow, stable temperatures and relative humidity levels – is another way to control pests that enter the cannabis grow site. “To exclude any pests that come in when you blow air into your garden, you can apply filters and then purify the air so that no diseases enter the site,” Chandler said. He also noted that it is also important to prune under the canopy for proper airflow and irrigation. 

Another cultural management tactic is ensuring employees change into uniforms when they get to work so they do not inadvertently bring in any foreign substances. 

Incorporating Chemicals to Manage Pests 

Chemical control, another facet of pest management, involves the release of organic pesticides such as neem oils or mineral oil, azadirachtin, pyrethrins and spinosad. Each state has specific pesticide regulations, so it is critical to know what each specific state allows before obtaining a specific chemical pesticide. It is also vital for growers to be familiar with the pesticide’s mode of action, so chemistries can be used in a complementary way; knowing how they work and what each chemistry treats is essential, so as not to create adverse effects or make the pesticides ineffective.

Ludwig noted the importance of using the right instruments and qualified analysts when taking a sample extraction to ensure that the chemicals used fall under the state’s regulations. “There are a lot of parameters that you need to control, adjust and keep track of when you are conducting pesticide analysis,” Ludwig said. “A pesticide testing instrument can cost anywhere from $125,000 to half a million dollars, but it’s necessary if labs are serious about getting it right.”

The Mechanical Side of Pest Management

Exclusion, also referred to as quarantine, is a way of isolating any new crops so new plant lines are not interacting with plants that are already in the grow, and potentially contaminating the crop. Chandler notes that it is extremely important to properly introduce these new genetics so there is no risk of a pest outbreak. “When you bring in new plants, don’t bring them right into the bedroom; instead, build a specific room,” Chandler advised. “If you are building a facility, design a quarantine room, where new plants have limited employee interaction and no contact with the rest of the crop. Growers should also monitor new plants and spray them with pesticides, or use beneficial insects, and ensure that the new plants are clean before bringing them into the rest of the garden.”

Chandler concluded: “With a really solid plan that’s put together by experts in combination with the people responsible for growing and maintaining the crops, there do not have to be any crop losses. If you have a good plan and implement it successfully, even if you miss a few sprays or a few beneficial applications, your crops will be forgiving.”