How to get rid of pests?
This is your first time growing cannabis. You check your plants every day and feel relieved since everything goes well with them. However, you find one flying bug in your tent. Maybe you find one or two larvae on the soil. Is this bad? Is this the end? It is nerve-racking—you’ll have to battle with these bugs for the health of your plants.
Let’s introduce our most likely pest culprits in a grow tent:
- Fungus Gnats
- Spider Mites
- Root aphids
Read more to know How to get rid of pests now!
How to get rid of pests: Fungus Gnats
Fungus gnats are black flies (about 3-5mm in size) with long legs, similar to mosquitoes. They like moist soil, thus cannabis provides an ideal habitat for them. Fungus gnats themselves are not dangerous to people but they can be fatal to cannabis—the larvae eat roots and are responsible for creating root rot in cannabis. Once cannabis is infested by gnats the lowers leaves will turn yellow and fall off and its growth will slow.
How to get rid of pests: fungus gnats?
- Drying out your soil is the most effective way of getting rid of fungus gnats. However, cannabis is also thirsty if the soil is dry for too long so you can add some sand or perlite atop the soil so that the adult gnats can’t lay eggs (eggs require moist soil and a layer of sand will stay dry, drying out the eggs).
- Put some sticky yellow traps in your tent. Fungus gnats like yellow and they will fly to the traps.
- Spray insecticide on rotten places—this will effectively kill fungus gnats and prevent the spread of rot.
- Use four times diluted hydrogen peroxide solution and more than 60% alcohol solution to kill fungus gnats.
How to get rid of pests: Spider Mites
Spider mites are tiny—they are usually less than 1mm in size so it is hard to see them with the naked eye—you’ll only be able to identify what they look like through a microscope. Although they are small in size, they are some of the most devastating pests to your plants. Spider mites like to live in a warm and dry environment so keep an eye out if you’re having trouble holding humidity up.
These mites like to attack the underside of leaves, sucking plant sap for sugar. Your plants will start to die once a large number of mites infest a certain area.
If you find these symptoms, then your plants are likely being attacked by spider mites:
- Some of the cannabis leaves turn yellow
- There are yellow spots on the leaves
- There are black or red or yellow spots on the back of the leaves
- There are white cobwebs on the top of the leaves—your cannabis won’t bud and flower due to these cobwebs because they obstruct airflow, meaning reduced yields at best or death at worst.
Now check out how to get rid of pests!
How to get rid of pests: spider mites?
- Don’t use pesticides—pesticides can’t kill mites since they quickly build a tolerance, so we recommend organic methods.
- Cut and remove the infested leaves/stems. If the entire plant is infested, don’t hesitate to throw it away, this will give your other uninfected plants a better chance to survive.
- There are many natural pesticides on the market that can kill spider mites without hurting your plants such as Pyrethrum, cinnamaldehyde, and neem oil.
- You can also wipe the underside of infested leaves with a clean cloth dipped with alcohol to kill the mites but do be careful since alcohol can also damage the plants.
- Another common way to kill spider mites is with ladybugs. It sounds surprising but it is actually a good idea—ladybugs are voracious predators and would love to eat the mites. They will stay on the leaves until all the food is gone and then will die off, or you can catch them and release them outdoors. They can bite you too, but it is no worse than a nip.
How to get rid of pests: Root Aphids
Aphids that attack cannabis are usually green and can be difficult to find. Aphids suck fluid from plant tissue for food with their needle-like mandibles. They usually gather on the lower part of the stem and the back of the leaves and feed in groups. If the cannabis is severely damaged, the leaves will turn yellow and wither, the branches will shrink and deform, and the plant will eventually die completely. As they feed on plants, they also produce a sugary liquid that attracts a fungus called “soot mold.” The mold thrives in the aphids’ secretions, and mulching leaves suggests that it hinders leaf respiration and photosynthesis, exacerbating plant death.
Here’re all you need to know about how to get rid of pests.
How to get rid of pests: root aphids?
- Check your cannabis leaves and stems regularly and remove the infected parts once you see any white spots.
- There are special insecticide soaps on the market that are really useful: BotaniGard can be used together with other insecticides such as pyrethrum and neem.
- Cannabis may be affected by many pests, but they also have a lot of friends. Ladybugs are a friend of cannabis—they feed on aphids just like they feed on spider mites, whiteflies, and fly larvae. Each juvenile ladybug can eat 5 to 10 aphids per day, while adult ladybugs eat up to 50. A dozen ladybug eggs per plant are enough to control or eliminate the infestation entirely.
We have only listed three common cannabis pests but cannabis has far more predators than just these three—they’re just the most common. Other pests like thrips, leaf miners, and cabbage loopers can also damage your plants, and of course there are other pests like fungus and mold.
Before you plant, ensure a clean and sealed environment. Sterilize all your tools and containers and change your clothes before you enter your tent to make sure you don’t bring any outdoor pathogens into your tent.
If you can’t tell which pests your plants are suffering from, you can message us. We would love to help.
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Great way to get rid of those annoying fungus gnats. I always get them from bad soil.