Cannabis: Creepy Crawlies — Using Beneficial Insects in Your Cannabis Garden

While many cannabis cultivators strive for no insect presence in their garden, an increasing number of growers are using mother nature’s pesticides — predatory insects. Chemical pesticides are expensive, can be dangerous to apply and consume, and are not always very effective. The first thing you want to do when exploring beneficial insects is to make sure you are scouting your plants regularly; identifying exactly what pest you have is crucial to selecting the right predatory insect. Keep a log so you can track when and where you have outbreaks. Read below to find some frequently used critters to help with common cannabis problems.

Phytoseiulus persimilis

A predatory mite that feeds on spider mites; hatched larvae and nymphs will also eat spider mite eggs and nymphs. They have a lifespan of eight days in the immature stage and 36 days as adults. These mites will perform best in 70 – 85*F and a relative humidity of 60 – 90%.

Dalotia coriaria

Also knows as the Greenhouse Rove Beetle, this is a soil dwelling beetle that feeds on fungus gnats, thrips and root aphids. These beetles adapt well to many kinds of growing mediums, including rockwool and coco coir, which makes them excellent for cannabis production. The lifecycle of these beetles is completed in 21 days, with optimum conditions of 70*F and 40 – 90% relative humidity. Adult rove beetles consume 10 to 20 prey per day.

Amblyseius andersoni

This predatory mite feeds on spider and russet mites, as well as thrips. They have a wide temperature range tolerance, surviving in 45 – 105*F climates. However, the eggs will only hatch between 65 and 77*F. These mites feed during all mobile stages of their life. They are compatible with Phytoseiulus Persimilis, so you can use these pests together for extra impact.

Praying mantis

These are definitely one of the most interesting beneficial insects, and one of the few that you can see with the naked eye. Praying mantises don’t discriminate with their prey, and will eat all pests in front of them. They are carnivores, so they won’t do any damage to your plants, but they will start to die off fairly quickly when their food source is gone. The mantis prefers temperatures over 70*F.

Steinernema feltiae

These are predatory nematodes, a roundworm that lives in the soil. After applying to your medium, they will seek out your pests and penetrate them through any orifice or through their skin. They will then exude a bacteria that kills the pest, and feed on their remains. Predatory nematodes are great for fungus gnats and root aphids. These pests do not cause direct damage to the flower of your cannabis plants, but instead feed on the roots, which stunts growth and yield and are overall a nuisance.

Beneficial insects are much more effective when applied to your crop when pest numbers are still low. Plan ahead and use them as part of your garden maintenance plan, instead of a solution to a big infestation. When used properly, they can keep the numbers of pests in your garden to a minimum, if not completely eradicating them, which will save you money and reduce the amount of harmful pesticides applied to your medicine.