Even in the best-managed commercial cannabis cultivations, pest infestations remain a constant concern. When pests are not effectively managed, the consequences extend beyond just losing a valuable crop; they can also damage your reputation, lead to government intervention, cause batch failures, and necessitate costly product recalls. In fact, the expense of dealing with an outbreak often exceeds the cost of preventative measures by a factor of five or more. Implementing a proactive Integrated Pest Management (IPM) program is crucial to prevent economic losses.
With evolving state and federal regulations surrounding cannabis production, low-toxicity methods like biocontrols are becoming increasingly important to ensure regulatory compliance and safety for both consumers and workers. Unlike conventional pesticides, most biocontrols are exempt from federal Environmental Protection Agency registration. However, they are generally regulated by state agricultural departments, so it’s essential to consult with local regulatory bodies to ensure compliance.
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Is a Biocontrol Program Right for Your Facility?
When considering a biocontrol program, it’s important to evaluate the best strategies for implementation. Biocontrols, or biological controls, are beneficial organisms such as predatory insects, mites, nematodes, and certain types of fungi and bacteria used to manage pest populations. When properly implemented, they help control common cannabis pests like fungus gnats, root aphids, spider mites, russet mites, whiteflies, and thrips.
Beneficial organisms work in various ways to eliminate pests:
- Predatory mites such as A. californicus, A. swirskii, and A. andersoni can be used preventatively by placing breeder sachets within the plant canopy. These sachets contain a food source for the predators, allowing them to breed and emerge gradually, which minimizes labor.
- Parasitoid wasps like Aphidius sp., Encarsia formosa, and Eretmocerus eremicus turn aphids and whiteflies into mummies.
- Green lacewing larvae (Chrysopa carnea) are aggressive predators of many soft-bodied insects, including spider mite eggs.
- Parasitic nematodes (Steinernema sp. and Heterorhabditis sp.) and entomopathogenic fungi (Beauveria bassiana, Metarhizium anisopliae, and Paecilomyces fumosoroseus) invade and reproduce within insect pests, effectively killing them.
Large-scale horticultural operations frequently use biocontrols to manage pest populations. For example, a 100-acre strawberry farm in California used the predatory mite Phytoseiulus persimilis to control a spider mite infestation—an approach that is also applicable to cannabis cultivation.
When to Use Beneficials
Biocontrols are not a cure-all for pest problems and must be used proactively. The goal is to maintain a low population of beneficial organisms that continually monitor the crops for pests. For example, if you have A. californicus sachets in your plants and a government inspector inadvertently introduces a few spider mites, the mites will be taken care of before they become a significant issue. However, once a large pest population is established, beneficial organisms cannot keep up, and a knock-down spray treatment with a mild pesticide may be necessary. Horticultural oils are an effective choice in such cases.
Some Top Picks for Biocontrols
One of the most effective solutions for fungus gnats is the parasitic nematode Steinernema feltiae. These microscopic worms are applied through irrigation or a spray/drench combination and actively seek out fungus gnat larvae to kill them. They also target thrips larvae, providing an additional layer of pest protection.
Another favorite is Phytoseiulus persimilis, a predatory mite known for its voracious appetite for spider mites. Capable of consuming all life stages of spider mites, persimilis is especially effective during the clone stage to prevent spider mite outbreaks before flowering. Many large cannabis and tomato greenhouses use weekly shipments of persimilis to control localized infestations.
Common Pitfalls and How to Avoid Them
Growers often report mixed results with biocontrols, usually due to several factors. First, biocontrols are usually shipped overnight and must arrive alive. Always inspect shipments carefully with a hand lens, and contact the supplier immediately if there are any issues. Fresh nematode packages, for example, should smell earthy, not foul.
Second, the presence of persistent pesticides in the cultivation environment can inhibit the establishment of beneficial organisms. This is especially true for miticides like abamectin (Avid), which can remain active for extended periods indoors. Consult your supplier for specific pesticide concerns.
Finally, it’s best to start small when incorporating biocontrols, monitoring effectiveness closely with a hand lens and adjusting as needed.
The Benefits of Biocontrols in Cannabis Cultivation
Biocontrols do not harm cannabis plants or affect the quality of the final product. In over five years of managing and consulting for large-scale cannabis facilities, I have never seen crop damage or failed microbial tests due to beneficial organisms. While some growers are concerned about the costs and application details, biocontrols can be cost-effective when considering factors like labor, chemical costs, and restricted working hours.
Many traditional greenhouse operators successfully integrate biocontrols into their IPM programs, recognizing their benefits for the bottom line and consumer demand for chemical-free products. With the right expertise and collaboration, biocontrol programs can help cannabis growers avoid pest-related crop losses while meeting regulatory requirements.
Share Your Experience
Do you have a success story about using biocontrols in your commercial cannabis facility? Feel free to reach out via the email in my bio—I’m always interested in hearing about different approaches and would love to feature them in a future update.
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