Cultivating cannabis poses unique challenges when it comes to pest control due to the fact that Cannabis plants are grown for human consumption, and therefore, every effort should be made to grow cannabis without the use of harmful pesticides. To further complicate or confuse matters for growers, the fact that cannabis still remains illegal on the federal level contributes to an absence of specific pesticide safety standards.

By adopting Biological Control Agents, growers can attack harmful pests like spider mites by introducing other predatory mites, basically a good bugs versus bad bugs scenario. Controlling cannabis pests with beneficial organisms is a natural and organic method to kill and control harmful mites attacking your precious pot plants without the use of harmful chemicals.

Types of Predatory Mites

It is important to understand the behavior of predatory mites and the different types of beneficial organisms available before introducing them into your garden. There are three categories of predatory mites:

Type I – the first type of predatory mites feed only on spider mites in the Tetranychidae family, which includes Tetranychus urticae, the two-spotted spider mite. An example of Type I predatory mites includes Phytoseiulus persimilis, also called P. persimilis, which quickly responds to spider mite infestations. The P. persimilis feeds only on spider mites and cannot survive on any alternate food source; therefore, they will actually cannibalize each other and die off after reducing the two-spotted spider mite population.

Type II – these predatory mites will not cannibalize each other and feed on a broader range of mite pests as well as pollen. Examples of Type II predatory mites include N. cucumeris, Neoseiulus californicus, Galendromus occidentalis, and N. fallacies.

Type III – the third type of predatory mites feed on a wide range of mite pests, including russet mites (eriophyids), Polyphagotarsonemus latus, cyclamen mite, and Phytonemus pallidus. Type III predatory mites also feed on compounds produced by plants and pollen as an alternate food source. Examples of Type III predatory mites include Amblyseius swirskii, which feeds on Western flower thrips, sweet potato whitefly, and greenhouse whiteflies.

There are some exceptions to these generalized classifications. Learn more about how to fight bugs with bugs, including how to identify mite pests, predatory pests, and their ideal conditions, lifespan, and feeding habits from Cannabis Business Times.

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Preventive Measures Before Planting

To prevent a harmful mite infestation in the first place, make sure your grow area is clean and free of pest infestations. Remove any nonessential equipment, fungal residue, or old plant material that can promote pests and provide hiding and nesting spots. Use only clean pots, fresh and clean soil, and wash all tools and clothing to prevent cross-contamination between crops. Once you plant, you can start to introduce predatory mites, which provide many benefits such as:

• Predatory mites are beneficial organisms that are commonly found in nature and are organic.
• Mite pests have not developed any resistance or tolerance to predatory organisms as they can with pesticides.
• Predatory mites are persistent and typically require reapplication only occasionally.

Introduce Predatory Mites When Planting

As soon as you start planting cannabis seeds and have watered your first pots, add the first predatory soil mite, like the Stratiolaelaps, at a rate of 10 to 13 mites in each square foot area. They will prevent fungus gnat larvae at the roots and promote faster growth with healthier plants. Stratiolaelaps also feed on thrips larvae which helps to manage a thrip infestation by stopping the reproductive cycle. If you still encounter a spider mite problem, introduce more Stratiolaelaps to the ground area and any cracks in the floor where spider mites may hide.

If growing in hydroponic air rooting systems, it is recommended to introduce some rove beetles, also called Dalotia coriaria, which tolerate aquatic situations well, are always hungry, and are excellent flyers. They tend to remain in the structure and the drain system requiring only periodic reapplications to maintain their presence.

Once your cannabis plants start to show true leaves, growers should introduce Amblyseius fallacis, also called fallacis, at a rate of two mites in each square foot. Fallacis is a general spider mite that easily controls broad mites and other microscopic mites. Growers that have had a prior infestation of broad mites should double the rate of fallacis.

Growers should also implement yellow sticky traps with at least one trap to cover every 500 ft.². Traps should not be placed higher than the plants, or they will not catch thrips.

You can learn more about mite infestations and biological controls, including predatory mites, and how and when to introduce from Evergreen Growers Supply. Remember to start every grow with high-quality cannabis seeds from a reputable breeder such as The Seed Cellar.

The Seed Cellar is one of the largest online weed seed banks, with more than 3,000 strains from over 80 selected top breeders. High-quality cannabis genetics produce high-quality cannabis plants for successful results in a clean and pest-free growing environment. Check out our wide selection of cannabis seed types and strains and enjoy quality seeds delivered in original breeder packaging.