Cannabis Pests

Eventually, every grower will experience bugs. It’s especially hard to protect your plants against bugs outside.

But also indoor growers will be bothered by them. Probably no grasshoppers or slugs, but very small insects such as spider mites and thrips will always find a way to your plants.

Fortunately there are enough solutions and measures to minimize the damage.

Plants can also house bugs that aren’t harmful at all, and are actually really useful. Ladybugs love lice for instance.

Lice feed on the sap of the plant and damage it, but ladybugs are harmless.

In this course I’ll teach you what the most common bugs are and what you can do about these.

I’ll make a distinction between growing outside and inside, because there are some big differences.

Also, take a look at this symptom checker. This overview provides photos of all possible things that are harmful to your plants.

Think of nutrient deficiencies, bugs, diseases, fungi and climate problems.

Compare the pictures on the page to your own plants to make an easy diagnosis. A solution is provided for each problem.

If you’re not sure, just upload the picture to the forum, so other growers can have a look.

Growing outdoors

Planting marijuana outdoors has its advantages and disadvantages regarding the chance of damage caused by bugs.

The dangers outside are much larger, because all possible threats are present. But nature also has an answer to this.

For instance, there are enough birds that aren’t harmful to your plants, and eat those annoying slugs or caterpillars.

And ladybugs and frogs love to eat lice. Furthermore, plants have natural defenses against bugs. Good breeders take this into account when crossing species.

You have to take measures if you’re suffering from an infestation. There will always be a caterpillar that eats a leaf, that’s kind of part of the whole outdoor growing process.

But if you see trunks turning black from the thousands of lice, or if rabbits start eating your entire plant, it’s time to do something.

I always try to chase away the harmful bugs instead of killing them. But if there’s no other solution, use an agent that doesn’t lead to any innocent victims.

Here are the most common problems for outdoor growers.

Rabbits

These small creatures are everywhere and they love weed plants. They especially like young plants with many young side shoots. Adult plants aren’t bothered by rabbits.

A rabbit can easily eat 7 ounces of green fodder a day. That’s quite a number of young plants.

And the rabbits are never alone, so they can cause enormous damage.

I always protect my outside plants by surrounding them with chicken wire.

I increase the size of the cylinder once the plants grow and start poking their leaves through. Make sure to dig the wire into the ground a bit, so it won’t fall over.

Chicken wire also protects your plants against deer, cats and other rodents, and is environmentally friendly.

Sometimes I spray an agent based on chilli pepper, a sort of pepper spray. Mammals with a strong sense of smell, such as dogs and rabbits, will always avoid these spots.

You can buy this at regular garden centers.

Slugs

Slugs can also be very harmful to your weed plants. They feed on the leaves and can eat all leaves off your plant within days. It’s good to know that slugs also love beer.

Garden centers have special slug traps you can fill with beer. But you can also dig in a little bucket, filled with beer.

Make sure the edge is about 2 inches above the ground, so no other animals that are just passing by will fall in.

You can also sprinkle poison against slugs, but make sure you buy the right product.

Products based on ferric phosphate is only harmful to slugs and not to children, birds or mammals.

Products based on metaldehyde or methiocarb cause many innocent victims.

Hedgehogs that eat slugs containing metaldehyde will die and birds are also very sensitive to methiocarb.

Always try to find the most environmentally friendly solution.

Lice

Apids, or plant lice, are herbivorous insects. They feed on the cells of a plant and they’re usually black or green.

They’re only 0.02 inches in size and are usually located on the underside of the leaf. Plant lice look for the shoot of a plant, such as the top of a young stem.

They suck the nutrients and saps out of your weed plants. With every bite, the plant lice push saliva into the cell of the plant, thereby infecting it with viruses, weakening the plant.

You can buy 1500 ladybugs on Amazon and release them in your garden, but I’m afraid many of them will quickly leave the area.

I use Bug Control or another agent based on pyrethrins. Agents based on garlic or nicotine also work very well.

You could boil a handful of tobacco in water and spray it on your plants. Or put some onions and garlic in 32 ounces of water and let it sit for 24 hours.

Just make sure to spray again after a number of days. There will always be eggs on your plant that hatch after a couple of days, so you’ll have lice again.

Growing indoors

You won’t have as many bug problems inside. Slugs, rabbits and deer won’t sneak into your house as quickly.

But the smaller bugs, such as red spider mites, thrips and little flies can easily enter your growing room.

Once you have bugs in your room, they usually multiply very quickly, since the room has an optimal climate and they don’t have any natural enemies.

So the chance of bugs is smaller, but the damage is usually greater. I usually don’t take any risks indoors, and spray something on my plants that’s poisonous to the bugs.

I’ve released an army of ladybugs before and that worked just fine. The only weird thing is that they eventually burn, because they sit on the lamp.

It’s a good option if you’re growing with fluorescent lighting though.

Spider mites

These small creatures infect the plants. They’re barely visible, since they’re only 0.008 to 0.02 inches in size.

They’re located underneath the leaf and look like black or red dots. The mites thrive in warm, dry circumstances.

They suck the saps out of the leaf by poking a tiny hole in it. The leaves will eventually turn yellow, which will weaken the plant so much that it dies.

You can identify red spider mites by the little white dots on the leaf. Another clear signal is the formation of webbing on and around your leaves and buds.

If you see webbing around your buds, you’re in deep trouble, because the spider mites are in an advanced stage.

In that case, there are probably thousands of red spider mites on your plants and the plants will no longer look healthy.

Regularly check for spider mites. Look out for white dots on the leaf or black dots underneath the leaf.

If you give the red spider mite a little push with your nail, it will start to move. I use Bug Control or another agent based on pyrethrins.

Plant Protector

This powerful defense system makes it easier to produce a healthy crop with high-quality flowers and potent buds.

Buy plant protector

Agents based on garlic or nicotine also work very well. You could boil a handful of tobacco in water and spray it on your plants.

Or put some onions and garlic in 32 ounces of water and let it sit for 24 hours. Just make sure to spray again after a number of days.

There will always be eggs on your plant that hatch after a couple of days, so you’ll have spider mites again.

If you’re experiencing webbing, your leaves probably won’t look as healthy anymore, so you have to save whatever can be saved.

You probably can’t get rid of the spider mite completely anymore. Use a dry washcloth to remove all webs from the buds.

Then completely spray your plants with an anti spider mite agent, especially underneath the leaves. You’ll probably see even more webs right now.

Remove these as well and repeat this every other day until your plants are done or until the spider mites are dead.

Also try to mix up the pesticides, because the spider mites could become resistant.

Thrips

These little creatures belong to the smallest winged insects. They can cause a lot of problems in your weed plants. The thrips feed on plant saps.

They do this by scraping the leaves, creating a sort of silver grey spots on them. It looks a bit like the slime trail of a slug or caterpillar.

Their droppings are visible as black dots on the leaf. Their sucking on the leaves can slow down the growth and cause cosmetic damage. Some thrips can also transmit viruses.

I use Bug Control or another agent based on pyrethrines. Agents based on garlic or nicotine also work very well.

You could boil a handful of tobacco in water and spray it on your plants. Or put some onions and garlic in 32 ounces of water and let it sit for 24 hours.

Just make sure to spray again after a number of days. There will always be eggs on your plant that hatch after a couple of days, so you’ll have thrips again.

There are a lot of different bugs that can cause damage to your plants.

If you don’t recognize these symptoms or if you’re not sure what’s going on with your weed plants, feel free to post your question on the forum, where plenty of experienced breeders are willing to help.

Also check out the Symptom Checker to see if you can match it with the symptoms you’re experiencing.