Cannabis Pest Control and Prevention for Beginners

Growing and harvesting cannabis is a long process that requires a great deal of attention to detail and experience to succeed. But even for a skilled cultivator, one of the most frustrating aspects of growing in any environment is cannabis pests. 

Pesky weed bugs, insects, bacteria, fungi, powdery mildew, or viruses can latch onto your cannabis leaves and buds at any point of the harvest or flowering stage, which can often lead to serious plant damage or other issues along the way. However, if you are proactive, attentive, and in control of the situation, preventing pests from overtaking your plants is pretty straightforward and simple. 

Here are our best tips for identifying these unwelcome creatures, executing the proper cannabis pest prevention, and cannabis pest control to ensure your plants are safe and unscathed. 

Common Cannabis Bugs

Weed bugs are some of the most common offenders when it comes to cannabis crop takeovers, but as long as you know how to utilize integrated pest management (IPM) during flowering and other stages, your cannabis plants will be safe. Thankfully, they’re usually easy enough to spot with the naked eye, allowing you to take immediate action against their instinct to lay eggs and really hunker down in your grow rooms.

These are some of the most common weed bugs and insects that may pop up while growing cannabis and a few reasons they might be drawn to your marijuana plants. 

  • Russet Mites

Russet mites (a.k.a. broad mites) are notoriously small, and can actually be difficult to see without the aid of a microscope or magnifying glass. These pests like to hang out on the underside of leaves, laying eggs inside of the plant for an insidious effect.

If your plant is infested with russet mites, new growth can come in twisted or blistered and will appear wet or plastic-like. Your buds can also turn brown and die if the infestation occurs during the flowering stage. Pest control during the flowering stage takes immediate attention and a gentle solution.

Cannabis and hemp russet mites infestations tend to occur when your plant is overwatered, heat damaged, or deficient in nutrients. Unfortunately, due to their small size and tendency to quickly reproduce, these can be some of the most difficult pests to rid your crop of.

  • Leaf Miners

Living inside the leaves and tunneling through them to eat and survive are leaf miners, rendering them difficult to notice until the damage has been done. These pests tend to eat the best parts of the plant, leaving a trail of frustrating damage behind. 

Leaf miners will pop up when your grow room’s temperature is off kilter, so keep a close eye on these levels to help prevent these pests from running amok.

  • Fungus Gnats

Fungus gnats have transparent bodies, black heads, and are commonly found in plants that are overwatered. These pests thrive in dark, moist environments and are often found at the base of the plant.

Thankfully, it’s quite easy to rid your plants of fungus gnats without the need for tools or insecticides. Simply allow the top inch of your soil to dry out before watering, which can easily make them go away on their own. 

  • Spider Mites

Spider mites thrive underneath the leaves of your plants and are incredibly tiny, appearing like yellow, orange, or white speckles. These can easily be incorrectly diagnosed as a nutrient deficiency, so you may want to utilize a magnifying glass or microscope for the differentiation here.

Spider mites are quick to take over a plant or grow area and develop resistance against pest control methods, so it’s often recommended to attack them with the utilization of a variety of methods until they’re entirely gone. 

  • Aphids

Aphids are one of the most common pests to be found in your cannabis plants. They can feast on any part of the plant, from the top layers of the leaves to the undersides. 

These pests are oval-shaped and may or may not have wings. They tend to attack plants that are overfed with nutrients, sucking on the nutrient-rich liquids until your plant is weakened and ultimately damaged.

They also reproduce incredibly easily – anywhere between three to 100 times per day. To make matters even more difficult to deal with, aphids secrete large volumes of honeydew, which attracts sooty mold and can have a detrimental effect on your crop. 

  • Thrips

Thrips are most commonly found in indoor grow rooms where they attack cannabis plants. Much like aphids, they’ll attack overfed plants, feeding on their nutrients until the life has been sucked out of them entirely. 

Thrips are small and can either be dark, yellow, golden, or translucent, making them difficult to identify and differentiate. An easy way to identify them is with what they leave behind: shiny bronze or silver spots where they’ve bitten your plants’ leaves. Where thrips have attacked, your leaves will turn brittle and dark before crumbling.

Beneficial Insects 

It might sound counterproductive, but one of the best ways to rid your plants of insects is to throw more insects into the mix. Here are some of the most effective beneficial insects you can utilize to combat the toxic ones.

  • Ladybugs

Ladybugs love to prey on aphids and can eat up to 60 of the pests per day. You can easily attract these helpful bugs by planting dill or fennel nearby, or just securing a large batch of them and letting them do their thing in your cannabis garden.

  • Earthworms

Earthworms don’t necessarily help control pests, but they’ll have more preventative effects based on what they do to your soil. The worms break down organic material and allow for better water drainage, which can prevent a number of the aforementioned pests from making their way to your plants in the first place. 

  • Praying Mantis

A praying mantis will eat a wide variety of pests, making it a great solution for your issue. They can also be attracted by planting dill, fennel, or marigolds. 

Non-toxic Insecticides

If you aren’t keen on the idea of adding more insects into the mix, you can utilize some high-quality non-toxic insecticides with natural active ingredients that will mitigate the problem without damaging your plants.

  • Foliar Sprays

Foliar sprays won’t necessarily attack pests. Instead, they’re a great preventative measure, as they can be beneficial for plants suffering from nutrient imbalances. 

  • Neem Oil

Neem oil is safe, organic, and effective at attacking many bugs, molds, and fungi. Just try to avoid getting it on any buds, because although it is non-toxic, it can still have an altering and noticeable effect on the plant’s flavor and efficacy.

  • Insecticidal Soaps

Insecticidal soaps will weaken the outer shells of bugs, getting rid of the issue without leaving much residue at all. But same as neem oil, do your best to avoid getting insecticidal soap directly on the buds, or it may have an effect on flavor and efficacy. 

  • Companion Planting

Companion planting isn’t so much an insecticide as it is a preventative method: planting two plants close together for the benefit of one or both of the plants. This can help confuse and/or repel pests from attacking in the first place. 

What is the best overall pest control for cannabis?

There are quite a few ways to treat pest populations that have latched onto your plants, but the best pest control is always prevention. If you remain diligent and proactive about checking for pests and taking the right measures to ensure they don’t have a way in, you’ll have a lot less to worry about throughout the growing and harvesting process.