Beneficial garden insects for cannabis

Many indoor and outdoor cannabis growers wrongly assume that any insect found on your plant is hell-bent on destroying your crop. In many cases, such as thrips, aphids, gnats, mites etc these uninvited pests will damage and eventually destroy your crop. However certain beneficial garden insects will hunt down and eat these pests helping you maintain a healthy garden.

Read on for all you need to know about using beneficial garden insects to control pest populations on your indoor or outdoor cannabis plants.

How beneficial insects work

Beneficial insects work around the clock hunting and consuming any pests (or their larvae/eggs) that may be living on your plants or among the cannabis root network. Beneficial insects are an organic, natural alternative to chemical treatments. Many indoor and outdoor cannabis growers make use of beneficial insects to control pest populations, preventing them from reaching problematic levels.

As well as eliminating pests, beneficial insects may also help nurture companion plants (e.g. mint, red clover, dill, lavender etc) which are often grown alongside outdoor cannabis plants to deter pests. Outdoor growers in particular are often keen to see biodiversity in their grow locations and may routinely release a range of beneficial insects throughout the grow season to control pest populations. They may also plant some companion plants to encourage beneficial insects and natural predators to stay and breed.

Of course, the best approach to any cannabis cultivation challenge is prevention rather than cure. Growers are encouraged to monitor their indoor/outdoor garden as much as is practically possible. But from time to time, a pest outbreak can occur. If this happens then a timely release of the right beneficial predator insects could help you rescue a doomed crop.

How to introduce predatory insects to cannabis plants?

First you need to understand which pests have invited themselves to your garden. Be sure to understand if any plant damage you see is really pest-created or whether it is a nutrient issue.

The experienced cannabis grower inspects their plants carefully and regularly looking for any early signs of pests. Allowing a pest infestation to reach problematic levels makes resolving the matter much more difficult. But once you have identified the main pest threat you can take the next steps to eliminate them.

The most common pests found in cannabis grows include fungus gnats, aphids, green, black & white fly, caterpillars, thrips and the dreaded spider mite. The good news is that these pests can be eliminated by beneficial insects. However, the process will take some time so the earlier you tackle the pest outbreak (and the more inspections you carry out) the better.

Buying predatory insects online or from a garden centre

Once you are confident about the identity of your pests you can consider the options. Many growers order their beneficial insects online or buy them from a local garden/pet store.

Outdoor growers can select companion plants to plant around the base/near their cannabis plants, these will also attract beneficial predator insects. Dill attracts ladybirds/ladybugs which can devastate spider mite and caterpillar populations. Thyme, borage, dandelions, nasturtiums and others have similar abilities to attract the right type of insects.

Indoor growers also buy and release predators, preferably before the pests have become too established. One of the problems with an indoor grow room is that the optimised conditions can allow pests to thrive once they get a foothold. The presence of some natural predators controls and eliminates those pests.

Consider supplemental UVA/UVB light to control pests

Some growers add supplemental UVA/UVB lights to their grow room to boost terpene profile and cannabinoid content. Usually, this light supplementation is in the form of fluorescent tubes though some (admittedly very expensive) UV LED lights are starting to become available. Growers that use UV often comment that it tends to control pest populations by creating a slightly more hostile environment for them.

Can beneficial insects help to fight a cannabis pest outbreak?

Yes they can, but only if applied in time. Once the predator insects are applied they will start to reduce the pest population. However, problems arise if the pests are so well established that the predators can't reduce pest numbers quite quickly enough. In these situations, all you can do is monitor progress of your predator insects and hope they succeed before your plant health is permanently damaged.

Why should cannabis growers avoid chemical pest control solutions?

Who wants to vape or smoke cannabis that has been chemically sprayed before harvest? Whether you’re growing autoflowering cannabis seeds or photoperiod feminised seeds, all growers want to shoot for maximum quality standards and purity levels. In the case of legal, licensed growers, the grow license itself may even be removed if crops are found to contain dangerous contaminants. It’s clearly better to tackle the pests naturally with predators rather than chemically with insecticides. It’s even better to avoid the pest outbreak in the first place!

Many people prefer to grow their own cannabis at home from cannabis seed for 3 key reasons:

•    To achieve superior quality levels compared to the locally available cannabis.
•    To ensure they are enjoying pure, high-quality cannabis rather than adulterated weed which may have been sprayed with chemicals.
•    To ensure self-sufficient cannabis supplies for the lowest possible cost

Beneficial garden insects for cannabis chart

Here are some of the more popular predator insects used by cannabis growers:

However, it’s worth adding that growers in different parts of the world tend to face different pest threats and may have their own preferred local solutions (including companion plants) that work particularly effectively in their conditions.

Many growers, especially outdoor growers, will routinely release beneficial predatory insects throughout the grow season. A pro-active approach with beneficial insects is relatively inexpensive in relation to the value of the final harvest and will help to prevent pests get anywhere near problematic population levels. Indoor growers tend to monitor their gardens carefully and will buy/release beneficial insects as required.

Ladybugs (also known as Ladybirds)

Ladybugs/ladybirds are colourful flying Coccinellidae beetles with a characteristic red back and black spots. They are a popular insect with growers of all types and are easy to buy online

Ladybugs/ladybirds feast on aphids. If you ever have a problem with greenfly or any type of aphids then these are a great predator to deal with the infestation. Adult ladybugs can eat 60-70 aphids per day and will lay their eggs amongst any aphid colonies. That’s where the real damage is done. Ladybird larvae can eat up to 300 aphids per day as they gorge themselves with food on the way to adulthood. They will also eat eggs of other pests including thrips, mites, beetles and moths. The lifespan is 2-3 years.

Predator mites (Stratiolaelaps)

Predator mites are very small and difficult to see. Their main benefit is to remove spider mites, though many growers found it ironic that they need to use one mite species to defeat another. Spider Mites are a despised pest and the best way to treat them is to react as soon as they are spotted. Instead of using commercially available treatments, including oil and soap-based sprays, many growers prefer to place some predator mites (often supplied in bottles) directly on to the affected areas and wait a few days for the predator mites to degrade the spider mite population. Mint is one companion plant which tends to attract predator mites.

Predator mites have a short life span and may need re-application to the spider-mite infestations   if they re-appear. Many growers, especially outdoor growers, will use a blend of predator insects over the grow season to ensure that pest populations never get chance to reach problem levels.

Praying Mantis

These unusual insects have superficial similarities to stick-insects. They will consume pests of all types and will wait patiently without moving for hours for their prey as they defend their plants like sentries.

They thrive on caterpillars, aphids and whitefly. This makes them particularly popular with outdoor cannabis growers, many release a few at different stages during the outdoor season to ensure that there are always a couple patrolling their cannabis plot.

The Praying Mantis lives around a year, enough for an outdoor grow. They are easy to buy online or from pet shops.

Green Lacewings

Green Lacewings are delicate flying insects with large transparent and lace-like wings. They don't cause any damage to your cannabis plants, but the lacewing larvae have a voracious appetite for soft-bodied pests including thrips, whitefly, aphids, spider mites and leafhoppers. Lacewings are an effective multi-purpose beneficial insect for your cannabis plants. Once they have eaten their fill of cannabis pests, they create a cocoon and emerge as an adult lacewing which can fly, breed and produce more larvae. 100-200 eggs are laid by each lacewing female during their 4-week lifespan. The Lacewing eggs are usually laid among aphid colonies, allowing the freshly hatched lacewing larvae instant access to their prey.

Lacewings are usually sold in small bottles containing hundreds or thousands of eggs which can be applied directly to the affected plant areas. They are widely used in agriculture as well as in cannabis cultivation.

Rove Beetle (Dalotia coriaria)

Rove Beetles are small creatures, often with red and black colourations. They thrive on fungus gnats, these are a real pest to soil growers. So much so that many soil growers prefer to buy wood-free soil blends which tend to see fewer fungus gnat issues.

Rove Beetles grow from egg to adult in about 3 weeks, at this point they are able to reproduce. Adult females can lay up to 8 eggs per day. Rove Beetles are often used alongside other predatory insects to ensure a pest-free growing area.

Nematodes

Nematodes are popular with organic gardeners. They kill pests such as slugs, ants, fungus gnats and weevils without the need for any nasty insecticides or chemicals. Nematodes are microscopic creatures, they are supplied as a solid block (kept in the fridge) and mixed with water. This resulting water solution is rich in nematodes and is applied to the area around your plants, under rocks, at the base of plants etc. The nematodes act as parasites killing any nearby pest populations often acting on the pest larvae.

Organic cannabis pest and disease control

Remember that catastrophic pest outbreaks are relatively rare. Even when they occur there are options for the indoor and outdoor grower. Pest and disease control can be done using methods which won't contaminate your buds with dangerous residual chemicals.

If you’re a home grower who grows from cannabis seeds, then you probably won't need any convincing about the importance of clean buds. Legal licensed growers know that their reputation and license depend on their ability to produce safe, pure cannabis. That’s why use of beneficial insects to act as natural 24-hour predators patrolling your plants appeals to so many growers, both indoors and outdoors.

Use of supplemental UVA & UVB light (often used for 2-3 hours per day in late bloom) also produces hostile conditions for flying pests in indoor/greenhouse gardens. Indoor growers tend to inspect their plants on a daily basis, meaning that pests can be caught early. For outdoor growers it can be more difficult to inspect 3-4m tall monster cannabis plants, here beneficial insects and natural pest predators can be especially valuable.