Many growers are increasingly choosing to use beneficial insects as a method of pest control. They provide a safer, more natural option than chemical pesticides while still protecting your cannabis crop.
While beneficial insects work best as a preventative tool, they can also be used as a last resort to treat active pest outbreaks. Depending on the species, they may need specific environmental conditions to perform at their best.
Rove Beetles
Rove beetles are predators that feed on fungus gnat larvae, which can be a big problem for cannabis growers. They can also help keep thrips at bay.
These beetles are a member of the Staphylinidae family and can be found throughout the world in various habitats. They are a very important part of nature and can help improve the quality of your garden.
They do not have stingers but can release a foul-smelling liquid to deter predators. This can be toxic if it comes into contact with your skin.
The rove beetle is a generalist predator that can consume a wide range of insect pests that live in your growing medium. They are especially effective at consuming fungus gnat larvae, but they can be used to control other soil-borne pests as well.
A rove beetle’s life cycle includes four stages: eggs, larvae, pupae, and adults. Female rove beetles lay their eggs in decaying organic matter and soil near areas where there is an abundance of a pest they prey on.
Most species of rove beetles are insectivorous, but some will eat carrion and some even parasitize insects. These beetles can be useful in gardens because they prey on small insect pests that destroy plants and cause a lot of damage.
These pests can be difficult to remove, but you can use rove beetles to get rid of them. Simply add a few rove beetles to your soil and let them do their job.
Insects that can be controlled with rove beetles include fungus gnats and thrips, but they can also help control aphids. Insecticides can be very costly and can take a long time to eliminate aphids, so using rove beetles as a preventative measure is the best option for your cannabis cultivation.
If you do find aphids in your cannabis garden, a good way to treat them is with *Met52 EC or *PFR-97 Microbial Insecticide. These products will kill aphids and their larvae, but you can also try releasing predatory soil mites into the cannabis patch to help control root aphids as well.
Lacewings
Lacewings are beneficial insects that can be used to control pests in cannabis cultivation. These predatory bugs can eat a variety of insect pests, including aphids, mealybugs, whiteflies, and spider mites.
These beneficial insects are a great addition to your plant health and pest management program, but they must be released soon after hatching to maintain a healthy population. Adult green lacewings are vegetarians and feed on nectar, pollen, and honeydew, but their larvae patrol plant foliage for soft-bodied insect pests. Once hatched, they feast on prey – pest eggs, nymphs, or adults – and spin a cocoon before emerging as adults 10-14 days later.
The green lacewing Chrysoperla rufilabris is the most common type of lacewing that gardeners use to fight aphids and mealybugs. Their larvae are incredibly effective in aphid control, but they also eat other soft-bodied arthropod pests such as whiteflies and scale insects.
They can be purchased as eggs, larvae, or adults. The choice depends on the pests you want to combat, when they’re most likely to appear, and how you want to apply the product.
When applied to cannabis leaves, green lacewings can kill or greatly reduce the populations of many pests. However, they will eventually die if left unattended, so it’s important to release them as early as possible in the grow.
Lacewing releases are most effective when paired with companion planting and cover cropping. Companion planting helps to attract a diverse set of beneficial insects, while cover cropping allows lacewings to stick around throughout the growing season and lay eggs for future seasons.
The use of neem seed meal, a high-quality soil mix, and other amendments is also a beneficial pest management technique that can help your plants to fight off fungus gnats, thrips, and pest mites. These nutrients provide a variety of macro and micronutrients and strengthen the immune system of your plant to prevent disease, stress, and damage from pests.
A few drops of neem oil can be applied to aphid-prone plants to deter aphids and other pests. Neem oil can be purchased in a spray form and is especially useful when applied to cannabis buds.
Assassin Bugs
Assassin bugs are an excellent group of predatory insects that attack a variety of pests. They are a popular choice for gardeners looking to use beneficial insects as part of an integrated pest management (IPM) program.
Typically ranging from 1/2 to 1 inch in length, assassin bugs belong to the family Reduviidae, or “kissing bugs.” These slug-like insects are characterized by a long rostrum that acts as a weapon. This elongated proboscis injects a toxin that liquefies the body fluids of their prey, which they then suck up through the rostrum.
While most species of assassin bugs are gray to black in color, a few are brightly colored. One group of assassin bugs known as ambush bugs sits on flowers, camouflaged by the petals, to wait for their unsuspecting victims.
These predators can be a nuisance, especially in large-scale cannabis cultivation where their presence is often not noticed. However, they are helpful in reducing the population of common pests such as broad mites and two-spotted spider mites.
A quick stab from the assassin bug’s proboscis immobilizes its prey, and it then injects a toxin that kills the victim within seconds. The body fluids of the prey are then drawn through the rostrum, which the assassin bug uses to eat its fill.
Assassin bugs eat a wide range of prey, including aphids, caterpillars, cucumber beetles, earwigs, and leafhoppers. These predators are also adept at hunting down and eating moth eggs, beetle grubs and insect larvae.
Most assassin bugs are harmless, but some are venomous, including the wheel bug and the elongate assassin bug. These bites can be painful and cause swelling, itching or hives. If bitten, wash the area thoroughly and apply antiseptic medication. If the wound is severe, seek medical attention immediately to prevent infection.
Another benefit of assassin bugs is that they do not prefer particular types of vegetation, and can be found in orchards, vegetable gardens, ornamental flowerbeds, and even outdoor container plants. Because they are so versatile, they make a great addition to any grower’s arsenal of natural pest control methods.
Nematodes
Many cannabis growers, both indoors and outdoors, are keen to reduce the use of pesticide sprays. Chemicals contaminate buds, and can leave harmful residues behind. Alternatively, growers can control pests without risking their plant’s health by using beneficial insects as natural pest predators.
Beneficial garden insects are naturally attracted to specific companion plants and can often be a cheap and effective solution for combating certain pests on cannabis plants. For example, dill and dandelions attract ladybirds and ladybugs which are particularly helpful in depleting spider mite populations. Borage, thyme and nasturtiums are also good companion plants that can be used to attract predator insects.
Nematodes are tiny worms that live in the soil and have a wide range of host plants. They can cause plant damage, and they may affect growth of a crop when they feed on roots, stems, leaves or flowers.
They rarely cause identifiable symptoms on cannabis, but they can disrupt plant growth and lead to a decrease in yield. They can also affect the quality of a harvest, as nematodes can cause stunted or distorted leaves and stems.
There are a number of beneficial nematodes that are specifically designed for use in cannabis cultivation. These nematodes have high compatibility with other beneficial organisms and can be a valuable addition to a grower’s IPM program.
In general, nematodes are microbial grazers and enhance nutrient cycling by eating organic residues that would otherwise be available for plant uptake. Nematodes can also re-establish microbial populations in the soil that have been lost to disease, decomposition, or fertilizer runoff.
Depending on the soil type, the amount of time between harvest and application, and other factors, nematode populations can vary widely. A nematode population that is too low to cause significant damage will not be noticed, while a nematode population that is too high can be detrimental to crops.
Some nematode species are known to be damaging to certain crops, and nematode testing is necessary before planting cannabis seeds or seedlings. The nematode that causes the most serious damage to industrial hemp crops is a type called M. incognita, which can be found in soils of varying pH levels and can cause root galls on some varieties of hemp.
