Cannabis growers are prohibited from using chemical pest control products on their crops since the flower cannot be washed before consumption or processing, and chemical residuals will be present in the final product.

If you’re growing somewhere that does not yet prohibit the use of chemical pesticides and fungicides, anticipate that they’ll soon be prohibited

Even organic-based pest control products can be problematic for commercial cannabis growers.

Spray applications made late in the flower cycle run the risk of failing microbiological tests before releasing a batch for sale. Furthermore, late-season sprays can burn delicate pistils and decrease the visual quality of the flower. Applications of organic pest control products like sulfur or rosemary oil also carry the real risk of changing a strain’s unique aroma.

Biological agents can help growers avoid these risky situations through preventative control.

Biological agents are beneficial insects, fungi, and bacteria that support crops by naturally protecting them against damaging insects and pathogens. These agents can be applied in a manner that does not run the risk of negatively affecting final flower quality.

Predatory, or beneficial insects, are bugs that prey on plant-damaging insects. There are dozens of insects that present a threat to cannabis crops, and fortunately, there are dozens of predatory insects that can be used to combat these pests.

Which species of predatory insect the grower should use depends on multiple factors—the most important being a question of availability. Not all countries allow the import of beneficial insects, and not every country has a domestic supplier of these insects. If a company breeds and sells predatory insects domestically, they may not carry every species that a cultivator needs.

There are also numerous factors that determine the efficacy of beneficial insects within a cannabis crop, such as release rates, timing, and environmental conditions.

Cultivation entrepreneurs should skip the guesswork and seek the advice of a company that sells predatory insects. They will prescribe a release and monitoring program to help protect your crop against the most common pests in your region. They will also help identify potential complications that could kill the beneficial insects or mitigate their effectiveness once they’re released—such as high temperatures, low humidity, or non-compatible products applied to the crop.

Growers should keep in mind that predatory insect programs only work when implemented preventatively. Beneficial insect populations need to become established in a cultivation site before damaging insects appear. Damaging insect infestations cannot be treated curatively with beneficial insects.

Koppert Biological Systems (koppert.com) and BioBest (biobestgroup.com) are two of the largest beneficial insect suppliers worldwide. I’ve used them on several occasions and continue recommending them to my clients.

Biological controls go beyond just insects to include naturally-derived products that inhibit or interfere with infection by plant pathogens. They operate through means such as parasitism, competition, and the production of antagonistic chemicals. Biological controls are typically bacteria or beneficial fungi that prevent foliar and soilborne diseases to which cannabis crops are susceptible.

Mycorrhizae fungi produce thin filaments called hyphae that penetrate the cell walls of plant roots, forming an extension of the plant root system. This symbiotic relationship assists plants in the acquisition of nutrients and water, which can lead to improved health and increased resistance to disease. In exchange, the plant feeds the fungus sugars that it produces during photosynthesis. The product is applied directly to the roots in powder form at the time of transplant.

Bacillus subtilis is a bacteria that is used to control devastating foliar diseases on cannabis plants, such as botrytis. It produces antibiotics that kill or reduce the growth rate of competing microorganisms, thus hindering spore germination, and preventing pathogens from attaching to the plant. It is applied to the crop during the vegetative growth phase, giving the bacteria a chance to populate the plant surface prior to the onset of flowers.

Trichoderma is a beneficial fungus that grows on the surface of plant roots and is applied preventatively by growers to control root diseases and enhance plant growth. It colonizes the roots of the crop, limiting space and nutrients for harmful soilborne fungi. It also triggers the plant’s natural defense mechanisms and helps to parasitize and kill plant pathogens. Just like the symbiotic relationship of Mycorrhizae, Trichoderma lives on food secreted by the surface of the roots.

Pest and disease infestations are part of growing any commercial crop, but the lack of permissible pest control products for cannabis can make control a challenge.

Smart growers plan early and incorporate live insects and biological agents into their cultivation programs to lessen their reliance on wet sprays.

Commercial cannabis growers should anticipate continued restrictions on traditional fungicide and pesticide products, so if you’re not already using biological agents to protect your crop, now is the time to start!