Cannabis Plant Pests and What to Know
Cannabis Plant Pests and What to Know
Cannabis is an adaptable plant that can thrive in various climates around the world and is popular amongst many species, other than humans. Though, adaptable does not mean impenetrable from outside forces such as pests, diseases, and natural weather phenomenon’s. Common cannabis plant pests and disease can pose a significant threat to the plants themselves and their life cycle during growth. Pests such as aphids, fungus gnats, and many more will be covered below along with information on how to combat their arrival.
Common Cannabis Garden Pests
Aphids, thrips, fungus gnats, oh my! Cannabis plant pests like these can inflict damage to indoor and outdoor gardens and can cause poor results in cannabis plants.
We decided based on the yearly inquires, we’d write out the Cannabis Plant Pests and What to Know Assistance Guide(s). Perfect for anyone looking for plant help! Each title is linked to additional information on each individual pest listed below. This is to help ensure you’re able to find as many helpful tips and tricks possible to celebrate another successful year of growing.
Aphids
Aphids are incredibly small, soft-bodied pests that are known to take over a wide variety of garden plants, including cannabis. A variety of colors can be found on these guys as the seasons keep moving. Winged or wingless aphids can be found on Cannabis leaves and stems; feeding off the fluids of plants with their “piercing-sucking” like mouth.
During the feeding process, none to very little injury occurs to the leaves. While many other pests show obvious signs of intrusion, with white flecking or surface scarring, on the damaged area of the plant. Along with loss of fluids, a significant number of aphids can result in wilting, slowed growth, and even leaf discoloration. The quickest way to diagnose aphids in your garden is watching for a sticky fluid, known as honeydew.
Honeydew is excreted continuously as the cannabis aphid feeds. Tiny droplets of honeydew form and disperse along the surface of the leaf. This fluid leaves behind small, but noticeable, shiny spots.
During their life cycles, aphids continue to grow and periodically shed as they produce a new, larger, exoskeleton.
Hemp Russet Mites
Hemp Russet Mites are tiny pests that are apart of the eriophyidae mite family. Eriophyids are known to be pale bodied (yellow and pinks are common), cylindrical with a sharply tapered off rear, and exceptionally tiny. Unlike many mites, Hemp Russet Mites only have two pairs of legs near their heads, rather
than four.
During low mite populations, damage will be difficult to notice. With larger populations, the affected area will be exceptionally more noticeable. Hemp Russet Mites will fed on the surface of the leaves by piercing and extracting cell contents. Symptoms of these heavier populations include:
- Bronzing (Russetting) – This can occur in stems as well if fed on
- Reduced Leaf Size
- Brittle Foliage
- Upward Leaf-Edge Curling
These pests do not produce webbing, unlike many other mite variations. Large infestations will also have an abundance of cast skins (exuviae). Since these pests are so small, exuviae can appear dark and powder-like on leaves and stems. This can be helpful when narrowing down the culprit. If not treated quickly enough, they can significantly reduce the plants yields and quality.
In smaller quantities Russet Hemp Mites prefer the underside of the cannabis/hemp leaves. But, as they expand their colonies, they move to other areas of the plant such as upper sides of leaves, stems, and buds.
Fungus Gnats
These pests are very small and resemble a fruit fly in size, and their larvae are even smaller. Fungus Gnats can be either grey or black and have long legs and antennas that give them a smaller mosquito-like appearance. Their larvae have small, black heads with a thin white or translucent bodies.
Fungus Gnats spend most of their time on the surface of potted soil and flying through the outer edges of the pot or near drainage holes. These pests are not strong fliers and usually only fly short periods of times, opting to walk around when able. Their flight pattern reflects one of a mosquito, rather than a fruit fly, despite the size.
Cannabis roots are not the first choice food for the larvae of these pests. Fungus Gnat larvae will choose the fungi and decaying matter within the soil first. Adult gnats are harmless to plants in the sense of damage, as damage only occurs when the fungus and decayed materials in the soil are depleted. When the roots of a cannabis plant are compromised during development, it can affect a plants ability to uptake the necessary water and nutrients. This causes wilting and even stunted growth to the affected plant.
Indirect damage caused by feeding larvae can also introduce infections and diseases to the plant through wounds. The damage caused can vary due to:
- Plant Age
- Plant Size
- The Number of Larvae Present During Feeding
Spider Mites
Spider mites, like many mite varieties, favor stressed plants and hot, dry conditions. As more climates around the country shift warmer as the years pass, more areas are experiencing these pests when previously, they haven’t been a problem.
It’s typical to notice damage to plants before seeing these pests on them. Spider Mites feed on the contents of the epidermal cells of the plant. The feeding process removes chlorophyll and causes small white spots to appear on the surface of the leaf. Once real damage has been made, the leaf will not recover nor regain its green color.
Spider Mites received their name based on the webbing they form when infesting garden plants. This is an easy way to help specifically identify these mites. Visually, these mites can appear tan, green, or red and typically have two spots on their backs. These marks on their backs are another easy way to identify these mites from other variants. Spotting adult females are easier than males as they are larger and rounder.
If you think you’ve eradicated your problem, keep a close eye anyways. These mites are known to come back full throttle.
Thrips
Thrips are tiny, (typically) winged, fast-moving insects that are about only 1-2 millimeters long; their bodies narrow in shape and their wings fringed. These tiny pests can be dark colored, yellow, transparent, or even a golden color. These pests won’t completely destroy cannabis plants, like Russet Mites or Powdery Mildew, but they will reduce the quality and quantity produced from your plant. Luckily they can be pretty easy to identify as the lack other characteristics pests may have.
A solid sign thrips may be invading your garden are white/yellowish bite marks and black dots known as excrements. Bite marks can cause the leaves to look smooth and shiny or even “slimy” looking. These bite marks will not be uniform and typically near the edges of the leaves. Thrips also do not leave behind honeydew, unlike many other biting insects.
Easily enough, a quick shake to your plant can also uncover these pests as they hop from branch to branch. They can be primarily located at the top of the plant under leaves and stems. Spring is the beginning of the thrip season and it is best to stay vigilant and always observe your plants as the season progresses.
Conclusion
As our climate continues to shift, new challenges arise every year. While cannabis is adaptable, so are the pests that invade it. It is always best practice to regularly observe and check on your plants during their life cycle. This ensures that any possible pests or problems can be identified quickly and efficiently to help avoid loss and reduction in quality and yield. Jewelers loupes, magnifying glasses, and even cell phone cameras (zoomed in) are great tools to closely inspect leaves for tiny pests such as mites.
