When growing cannabis, you should regularly check your plants for signs of cannabis diseases. This way you can prevent your plant from getting damaged and having to give up your harvest. In this post, we'll explain which cannabis diseases are common, how you can recognize them, and what you should do if your plant is sick. We will also discuss pest infestations, as they can also cause significant damage to your cannabis plant.
An easy way to protect your plant from diseases is to use Bonsanto Premium Soil. Our grow soil is composed in such a way that no diseases can develop, because the ingredients of the soil counteract the development of diseases.
Table of contents
What are the most common hemp diseases?
Depending on how and where you grow, hemp diseases can vary. The most common diseases are hemp mold, root problems, leaf septoria and TMV.
Hemp mold is the appearance of mold on your plant. Hemp mold is to be avoided for several reasons. Firstly, the quality of the plant suffers due to the mold infestation, so the taste and aroma of the plant will be worse. Secondly, the cannabis plant grows slower, resulting in low yields. As everyone knows, mold is also dangerous to health, because harmful substances are produced by the mold, which are unhealthy for us humans. The best known molds are powdery mildew and blossom rot.
Powdery mildew, or peronospora, manifests itself as a white, fine powder on plant leaves and often occurs in humid environments and when humidity is too high. This type of mold spreads by spores that can be transmitted in a variety of ways.
Blossom rot or so-called gray mold affects the flowers of your plant. This hemp mold usually occurs during the flowering phase. The buds are affected by mold, rot and die.
How to detect hemp mold?
- Gray, black, brown mold spots on leaves, stems or even buds.
- Musty smell on the discolored patches
- The discolored spots are wet
- Deformed leaf growth
- Powdery mildew: floury white coating on the leaves
- Blossom rot: brown, soft, rotten buds
What to do with hemp mold?
- Remove moldy parts of the plant if the mold infestation is not yet advanced
- Use fungicides suitable for the cannabis plant when the infestation is large
How to avoid hemp mold?
- Good drainage
- Bonsanto Premium Soil
- Adequate irrigation (You can learn more about irrigation in the blog post "Pour cannabis")
- Good ventilation
- Avoidance of overfertilization (You can learn more about fertilization in the blog post "Fertilize hemp for a bountiful harvest".)
- Regular check for signs of mold
Cannabis root problems
Root problems are also among hemp diseases, because healthy cannabis plants have strong roots. When root problems occur, the health of your cannabis plant is at risk.
Causes of root problems can be soil, size of the pot, watering or temperature. If the temperature is too high, you run the risk that the roots of your plant can not absorb enough oxygen. Cold, on the other hand, can shock the roots. Too much watering and lack of drainage can lead to drowning of the roots. If you don't use good growing soil, this can also have negative consequences on the roots of your plant, as they can't get enough oxygen from the soil.
A root problem of cannabis plants is root rot. Too little oxygen and too much watering can be the cause. Unfortunately, this problem is difficult to detect because the roots are not directly visible in the pot. Root rot can manifest itself in unhealthy and floppy looking plants.
How to recognize root problems?
- Yellow discolored leaves
- Withered and falling leaves
- Brown spots on the leaves of the plant
- Musty smelling and brown roots
- High humidity and mold growth in the root zone
What to do about root problems?
- Drainage improvement
- Better ventilation
- Repotting the plant in a new pot with fresh soil
- Cutting off broken roots
How to avoid root problems?
- Good drainage
- Bonsanto Premium Soil
- Controlled and appropriate irrigation
Foliar septoria is a fungal disease that causes yellow or brown spots on the leaves of your cannabis plant that spread over time. Since leaf septoria is resistant to many fungicides, it can be difficult to treat.
How to detect leaf septoria?
- Yellow and brown spots on the leaves
- spots with black dots
- Falling leaves
- Spreading from the bottom up
What to do about leaf septoria?
- Remove leaves affected by the fungus with sterile scissors
- Avoid contact of infected leaves with other parts of the plant
- Use fungicides that can control leaf septoria
- Ensure good ventilation
How to avoid leaf septoria?
- Good air circulation and ventilation
- Cultivation with clean equipment and accessories
- Avoidance of overwatering
- Proper plant care to avoid stress
Tobacco mosaic virus (TMV)
TMV virus is also one of the common hemp diseases. TMV is persistent and can persist even in heat. The virus is transmitted through infected plants, contaminated objects or aphids. Especially in the summer and fall months, the TMV virus transmits quickly. Once your plant is infected with TMV, growth suffers and your plant is weakened. Although the virus does not pose a health risk to humans, an infestation is nevertheless annoying because the harvest will be small.
How to detect TMV?
- Slow plant growth
- Deformed leaves
- Annular yellow-green spots
- Mosaic yellow spots
What to do about TMV?
- Separate healthy plants from infested plants
- Clean your plant accessories regularly so that the virus does not spread further to other plants
How to avoid TMV?
- Clean and hygienic cultivation
- Testing for pests such as aphids that transmit the virus
- Growing TMV resistant cannabis strains
Pests can also infest your cannabis plant, harming it and causing disease. To prevent pests from causing problems, you should regularly check your plants for them to be able to intervene early.
There are a number of pests that can occur when growing cannabis. You can find out what they are here. Treatment for most pests can be done through insecticides, soap sprays, or adding natural enemies.
Cannabis Scale & Aphids
Scale insects are white, yellow or red insects that infest the branches and stems of your plants. They feed on the sap of your plant, which can cause problems. They are difficult to spot because they produce a shield of wax to cover themselves with. Therefore, you can hardly notice a scale infestation on your plant. Aphids infest your cannabis plant on the underside of the leaves and also suck sap out of your plant. They can come in different colors and sizes.
There are a few clues you can use to tell if your plant is infested with scale or aphids. You may be able to spot them with the naked eye. If not, yellow leaves and slowed growth can also provide clues to scale insects. Deformed leaves are an indication of aphids. Since aphids produce honeydew, you can also identify an infestation by this sticky substance.
To control infestations of scale and aphids, you can use insecticides or a soap spray. Natural enemies of aphids include ladybugs and wasps, for example.
Cannabis smear lice
Pests that significantly harm your plant health are the white mealybugs. Because they produce and cover themselves with a woolly and waxy substance, the aphids look fluffy. You can recognize them by the same signs as scale and aphids and control them using the same methods.
Hemp broad mites
Broad mites are very small and therefore hardly visible either with a magnifying glass or with the naked eye.
If your cannabis plant is infested with broad mites, it can only grow slowly. The leaves take on a droopy and shiny appearance and look unhealthy. Since these mites can also infest the flowers of your cannabis plant, this can lead to flower drop. If you notice a broad mite infestation, you should act quickly and use a soap spray or insecticide.
Hemp rust mites
Like broad mites, rust mites are very difficult to detect. Therefore, it is not easy to detect an infestation. Drooping run and yellow discolored leaves can be a sign of an infestation. Slow growth and altered bud formation can also be indications of an infestation.
Cannabis spider mites
Spider mites can also infest your cannabis plant. In most cases they are brown or red. They nest on the underside of the leaves of your plant and leave white bites. Therefore, you can detect an infestation by small, white spots on the leaves. Fine spider webs left behind by the spider mites can also indicate an infestation. Since spider mites prefer high temperatures and low humidity, you should reduce the temperature and increase the humidity if you have an infestation. Soap sprays can also combat an infestation.
Whiteflies usually nest on the underside of leaves. They produce a sticky substance, which can attract mold and therefore harm your plant. If you move the leaves of your plant, they will fly up. To prevent them from settling back on your plant, you can use a soap spray or certain oils.
If your cannabis plant is infested with slugs, you have the advantage that this is quickly and easily noticeable. They eat the leaves of your plant and should therefore be removed so as not to harm your plant. You can easily remove the snails by hand and should therefore avoid the use of a spray.