News & Research

GreenSeal’s “Least Wanted” List

cannabis • July 31, 2019

Integrated Pest Management (IPM) safely prevents unwanted pests by recruiting their natural enemies

Like the Wild West of yore, when it comes to cannabis cultivation there are two types of insects: Good Guys and Bad Guys.

Whether they’re Good or Bad, they’re all a bit Ugly.

One of the big advantages of Canada’s regulated cannabis industry is the establishment of Good Production Practices (GPP) for production License Holders to follow.

Health Canada’s GPP requirements include specific rules governing the application of Pest Control Products (PCP).

The Cannabis Act explicitly states, “cannabis must not be treated with a pest control product unless the product is registered for use on cannabis under the Pest Control Products Act or is otherwise authorized for use under that Act.”

The fact is, most chemical pesticides are not safe for human consumption or exposure (and often cause environmental harm), so they are justifiably banned under the Cannabis Act.

To make sure License Holders aren’t using banned substances to control pests, Health Canada conducts regular, unannounced sampling and testing of product destined for the Canadian market.

If a License Holder is found to be using banned PCPs, the result could be a suspension or removal of its license, and/or a fine of up to $1 million.

Fortunately, experienced growers like the production team at GreenSeal already know the best and safest way to control unwanted pests isn’t through the use of chemical pesticides.

In nature’s ecosystem, insects that feed and/or breed on plants are usually kept under control by their natural enemies, which are often other predatory bugs.

Integrated Pest Management (IPM) is a technique that harnesses the potential for nature’s Good Guy insects (known collectively as “Beneficials”) to prevent and/or eradicate the Bad Guy insects that threaten indoor cannabis crops.

The list of Bad Guys threatening the health of indoor cannabis plants is usually topped by the following 5 Usual Suspects: Thrips, Aphids, Spider Mites, White Flies, and Fungus Gnats.

Our production team implements IPM practices every day to prevent the potentially destructive critters on the “GreenSeal’s Least Wanted” list.

As a constant reminder, five “Least Wanted” posters are displayed in GreenSeal’s common areas.

In addition to providing a visual for identifying potential pests, the posters also include information on the beneficial Good Guy organisms our IPM program recruits to fight the Bad Guys!

#5 Least Wanted: Fungus Gnats

GreenSeal Cannabis Co. Least Wanted Pests: Fungus Gnat

Adult fungus gnats have one mission: to breed.

The best conditions for fungus gnats to lay their eggs is in warm, wet topsoil.

Warmth and wetness are conditions that promote fungal growth, and fungus gnats earned their names because the adults feed and thrive off a diet of fungal material and decaying organic matter.

But once their eggs hatch and the larvae start to pop out, they will also soon start to feed on a plant’s roots.

Once a cannabis plant’s root system has been munched away enough, problems will appear in the leaves and growth will become slow and abnormal.

In the worst-case scenarios, fungus gnat infestations can cause the death of one (or all!) of the plants in a cannabis crop.

To control and prevent fungus gnats, GreenSeal regularly applies the beneficial organisms known as nematodes.

Nematodes are tiny flatworms that are mixed into water (in frozen form) and then added to our plants’ soil during the watering process.

If you’re wondering how living nematodes can survive being frozen and rethawed here’s a fun fact: Canadian researchers recently discovered nematodes in melting Arctic glaciers.

These organisms had been dormant for tens of thousands of years and were successfully revived in the lab (making them by far the oldest living organisms on the planet).

Once they defrost, our beneficial nematodes feast on fungus gnats in the larval stage, destroying them before they can devour a cannabis plant’s root system.

#4 Least Wanted: Thrips

GreenSeal Cannabis Co.'s Least Wanted Pests: Thrip

Thrips are known for piercing and sucking out the contents of cells located on the surface of leaves.

Their sap-sucking behaviours result in silver-grey spots appearing on the leaves of the plants they attack and a reduction in the plants’ productivity.

Thrips can be devastating if left uncontrolled, but fortunately there are several species of beneficial insects who love to eat thrips for breakfast, lunch, and dinner.

Nematodes are applied to eat thrip larvae before they can develop into adults.

The Swirski Mite (aka Amblyseius Swirskii), as well as its cousin Amblyseius Cucumeris, are the preferred predators for controlling thrips if they appear.

GreenSeal routinely applies all of of these beneficials as a preventative and control measures to stop and manage thrip problems.

When applied at the beginning of a growing cycle, these predatory mites feed on immature thrips and prevent the development of an established adult population.

#3 Least Wanted: Aphids

GreenSeal Cannabis Co.'s Least Wanted Pests: Aphids

Fungus gnats and thrips are not the only cannabis pest nematodes destroy and/or prevent.

Those tiny flatworms also like to eat the young of another species of nasty Bad Guy bugs known as aphids.

Aphids are determined critters: adult females will give birth to more female nymphs, and these nymphs give birth to even more offspring without the need for mating (known as “asexual reproduction”).

While some aphid species prefer the roots of plants, others feed on the plants themselves and hide away from sight in the undersides of leaves.

Aphids can cause leaves to curl, wilt, or turn yellow, and can stunt plant growth.

If there is an infestation of aphids (which fortunately doesn’t usually happen in an indoor growing environment) other beneficial insects (like ladybugs and predatory wasps) can be introduced as controls.

#2 Least Wanted: White Flies

GreenSeal Cannabis Co.'s Least Wanted Pests: White Fly

White Flies look like tiny white moths with yellow bodies; the easiest way to spot the adults is to shake a plant, which causes them to fly away.

An adult can lay up to 400 eggs, which are usually deposited on the underside of leaves in circular groups.

Like all of the pests on our Least Wanted list, the best way to fight white flies is to prevent them from establishing themselves in the first place.

Fortunately, the predatory mites GreenSeal’s production team applies to prevent and control for thrips – A. Swirskii – also prevent and control for white flies.

#1 Least Wanted: Spider Mites

Out of all the critters who can potentially get into a cannabis crop, spider mites are by far the worst.

Female adult spider mites can lay up to 20 eggs per day, and up to 100 eggs each over the course of their three-week reproductive life phase.

Considering that a spider mite egg can develop into an egg-laying adult spider mite in as little as 7 days, the importance of preventing them from ever getting a foothold in a cannabis production area is clear.

By the time you see the tell-tale webs indicating spider mite infestations, it’s probably too late to stop them.

To prevent spider mites from ever establishing themselves in our growing areas, we recruit the services of a the Cucumeris predator mite (since Cucumeris is used to control so many different pests, it is known as a “Generalist”).

Cucumeris prevent spider mites by eating their eggs before they hatch.

Integrated Pest Management: A gram of prevention is worth a kilo of cure

GreenSeal has been applying IPM practices and beneficial organisms preventatively since day one.

In addition to recruiting Good Guy predators to help us fend off the Bad Guys on our “Least Wanted” list, our team is also trained to maintain pristine personal and facility cleanliness to avoid introducing new pests into the growing environment.

Small sachets containing beneficials are hung throughout each row of our production canopy and our watering regimen includes a regular dose of nematodes into the soil of all our plants.

The effort we put into preventing the appearance of our Least Wanted pests is well worth it: as the saying goes, “An ounce of prevention is worth a pound of cure,” and this is certainly true for IPM (although in the Canadian industry we might change that to “A gram of prevention is worth a kilo of cure”).

Do you have any experience preventing pests from damaging your cannabis crops using natural methods?

If so, we’d love to hear about it – let us know in the comments below!

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