Treatment and Pest Control in Growing Marijuana

Pest infestation is one of the problems causing headache to several pot growers. Once the marijuana plants are infested with pests, totally eliminating them is not an easy job to do. Pests are hard to eliminate once they have attacked your plants. What you can do is to control them from multiplying and spreading in your entire cannabis garden.

Once pests have infested your cannabis plants, you will have a difficult time in eliminating them. There are several pest control methods available to eliminate pests. The use of predator mites is one. Other options include the use of organic pest control and spraying of insecticides.

Common Pests Affecting Marijuana and How to Deal With Them

Spider Mites

marijuana spider mites

These pests are very tiny, making them hard to recognize using your two naked eyes. They are usually caught from a different grow room, with bites that leave some small, white specks on the upper side of the marijuana leaves and are usually forming small webs which you can detect by water spraying. To deal with these pests, some growers remove them by hand. However, it cannot give you better results. The use of insecticides is one of the best pest control methods of eliminating spider mites. Phytoseiulus persimilis is a predator mite used to control multiplication of spider mites.


thrips in marijuanaThrips have wings and are small, fast-moving insects that love to suck young and fresh pot leaves. Young thrips look like tiny, fat worms. These small insects appear as shiny and silvery spots on the leaves. They may even appear like ‘dried spit’, or even small ‘snail trails’. Further multiplication of thrips can be controlled by using its natural enemy Amblyseius cucumeris. For maximum pest control, you can use insecticides.

White Flies

white flies in marijuanaWhite flies are easily recognized using your naked eyes. They act and attack weed plants in a way that spider mites do.

These insects can often be seen on the top side of the leaves. They appear as white spots and resembles like white moths.

To control them from spreading, you can use assassinator wasps called Ichneumon fly.

If pest control using assassinator wasps doesn’t work well, your next option is to treat the affected pot plants using insecticides.


aphids_in_marijuanaAphids are insects that thrive under the leaves of the cannabis plants. They often come in various forms, highly depending on their life stage.

There are organic remedy that you can use to get rid of aphids like tomato leaf spray, garlic oil spray, and many others. You can make your own spray if  you want to. However, we are not going to bore you on the details on how to create your own spray. That would be a separate blog post.

If you don’t want to go through the hassle of creating your own organic spray then you can buy bug repellents that will work well with aphids.

Scale Insects / Barnacles

bernaclesBarnacles are bugs that love to stick on the stems of the plants, as well as underneath its leaves. They will suck out the life in the stem and leaves leaving you with a mess.

The result will be like of that of the aphids which can cause dark patches in your plant. These insects also produce sweet sticky substances which is also known as honeydew. Since it is sweet, ants might also give your plant a visit.

Use a power sprayer to remove the barnacles from your plant. There are also other ways on how to get rid of them like insecticidal sprays, etc.

Russet Mites or Broad Mites

marijuana_mitesThese types of mites are very small that you will not see them with your naked eyes, or even when using a magnifier. However, you can still tell whether your plant is already infected or not because you can notice that the new leaves are twisted, blistered and glossy.

Overall, your plant will grow poorly. If it is already in the flowering phase, you will also notice that the buds turn into brown. Russet mites and broad mites are usually mistaken with other issues such as pH problems, heat stress, as well as nutrient deficiencies.

Mold or Bud Rot

When mold or bud rot strikes your plant, some of the buds may being looking sickly even overnight. The leaves may turn into yellow, while the buds may be discolored. When the buds are opened up, you can see that it is either moldy, or dead.

Cabbage Loopers, Caterpillars & Inchworms

What is common among these three pets is that they love to chew on the leaves of the plants. As such, their attack is quite obvious and visible. You can see holes in the leaves, and they even droppings which usually appear similar to that of black specks.


Crickets love to munch on marijuana leaves. However, you may notice that the appearance of the affected leaves may differ, depending on the type of cricket that attacked it. Regular crickets will just much on the leaves, but mole crickets may tunnel beneath the plants, going all the way down to the roots.

Fungus Knats

This fungus gnats usually look similar to tiny dark flies. They usually stay around the soil, as they love wet surroundings. They produce worm like larvae that crawls on the wet top soil. If the infestation becomes out of control, your plants will start to get sick.


Grasshoppers seemed to be quite harmless. However, they can actually eat your marijuana leaves away.


Leafhoppers come in different colors, which is why detecting them can be quite difficult. However, what makes them identifiable is that they make clusters of spots on the leaves. This is where they suck out the sap. Therefore, if you see spots forming clusters, then your plants are being attacked by Leafhoppers.

Leaf Miners

These leaf miners are actually larva which live inside the leaves, tunneling through all their parts, eating them from the inside out.

Treatment and Pest Control Solutions

Most of the time, you will find it difficult to identify the particular culprit of the pest attack in your plants. Good news, however, is that most of these pests can be controlled using common treatment options.

Use only sterilized fertilizer or soil

Usually, the problem with using unsterilized soils is that it may contain larvae or eggs of some of the mentioned common cannabis pests. If you end up growing your marijuana plants in these types of soil, you will surely be in for an unpleasant surprise the moment those eggs start hatching, or the larvae starts to grow up. This will be especially bad if you are growing your plants in an indoor growing environment you cannot take advantage of the presence of natural predators in the house.

Grow some companion plants

There are plants that are described as ‘natural repellents’. This is a good way in which you can keep the plant predators away. Even though the THC produced by your marijuana plants may serve as natural repellent by nature, its capability is usually not strong enough to be able to repel all of the plants, most especially if they are still in their earlier stages of growth. Among the plants that you can use include pungent ones such as marigolds and geraniums. They can keep those leaf-munching worms and insects at bay. You may also want to plant onions to keep those bigger pests away.

Use some natural predators

This is mostly applicable if you are growing your plants in an outdoor environment. Among the natural predators that you can invite to your garden include ladybugs, as they love preying on pests as well as larvae. You may also want to invite birds to nest in your garden because they love snacking on pests. For this, you can choose to install bird houses or bird feeders to allow the birds to come arrow. However, make sure that they are not around during the germinating phase of your seeds because they also love marijuana seeds.

Use the enemy’s urine

This refers to the enemy of the pest that is currently taking over your garden. While this may sound like a creepy joke, but this actually works. For example, if you are dealing with bigger predators, such as deers, these animals have keen sense of smell. If they detect a slight hint of their enemies smell, such as puma or bear urine, they will not come close to your plants.

Build a fence

If you are having problems with bigger animals attacking your garden, and you have already tried using the scent of their enemies and still they are not distracted, you might want to provide the extra protection by building a fence that will surround your plants. Quite obviously, several marijuana cultivators may not have this luxury. At the same time, this is only applicable to those who are growing their plants on a private area.

Make a repellent force field

There are some repellent solutions that can give you this outcome. For example, you can use a permethrin-based repellent that will keep your plants from insects without having the need to use synthetic spray. All you have to do is to spray on the ground, about a distance of 6 feet away from your plants. When bugs come in contact with this substance will flee away or die there.

Organic, custom repellents

Other expert growers also decide to use organic, yet pungent repellents in order to ekeep the pests away from their plants. This is applicable to both indoor and outdoor plants. There are some concoctions that you can make, such as cinnamon oil, coriander oil, clove oil, and others which have shown some relative success without further causing damage to your plants. In fact, you can spray these repellents quite easily on the leaves of your plants without worrying about any potential adverse reactions.

Keep in mind, however, that some strains may react to homemade repellents. Therefore, it is best to conduct a test on a particular section of the plant first, just to ensure that your plants will not be harmed along the way.

Bottom Line

Pests and Insects are bad news to your marijuana plants. Their presence will do harm to your marijuana growing project. Therefore, they need to be treated during the earlier phase of the infestation. If not, you might end up with poorly grown plants, or even worse, dead plants on your garden, or growing room.

Whether you decide to choose the currently available solutions, or go for natural means, it is entirely up to you. However, in order to make the best decision in choosing the solution, make sure that you identify the particular insect and pests attacking your plants first, and then visit forums where you can find information on specific treatment solutions for the specific pests. This usually works best than simply trying out on different products which may not work.

All in all, having a clean surrounding is one good way to prevent any pests from festering your plants. This is the reason why some aeroponic and hydroponic systems are recommended for growing marijuana, because they can prevent several types of infestations. After all, there would be no place for the larvae to develop and hatch. On the other hand, if you choose to grow on soil, it would be best to sterilize it first, composting it, or even buying pre-sterilized soil. You may also cover your soil using a layer of diatomaceous earth so that it can prevent crawling and flying insects from ever laying eggs because the sharp edges can damage the bodies through abrasion.

Also, make sure that you wash all floors, walls and surfaces with soap, or diluted chlorine bleach solution, or other disinfectant solutions. Depending on your surface, you may also want to cover the floor using 6 mm plastic sheet which can be bought from home improvement stores. This is also true with other items such as buckets, pots, utensils, and others. This cleaning procedure should be done on every new grow. Make sure that when you enter your growing room, do not bring anything from the outside, such as your work boots. With all of these taken into consideration, you can at least. Prevent pest control in your grow area.

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