What are nematodes?
Nematodes, also known as threadworms, are microscopic organisms that live in the soil. While some species damage plants by infesting roots, others act as natural pest controllers. For cannabis growers, it is crucial to distinguish between beneficial and harmful nematodes.
Harmful nematodes – a danger for cannabis?
Certain nematode species such as Meloidogyne (root gall nematodes) or Pratylenchus (root lesion nematodes) can severely damage cannabis plants. They penetrate the roots, hinder nutrient uptake and lead to:
- Stunted growth
- Yellow leaves
- Increased susceptibility to fungi
Beneficial nematodes – Biological pest controllers
In contrast, predatory nematodes such as Steinernema and Heterorhabditis are valuable allies. They parasitize pests such as fungus gnat larvae or thrips and thus reduce the need for chemical pesticides.
How do you recognize a nematode infestation?
Typical signs are
- Root deformations (nodule formation)
- Wilting despite sufficient watering
- Poor nutrient absorption
A laboratory analysis of the soil provides definitive certainty.
Combat & prevent nematodes
Biological methods
- Use beneficial organisms: Bacillus thuringiensis or predatory nematodes
- Plant rotation: cultivation of non-host plants such as marigolds
- Healthy soil: compost and mycorrhiza strengthen the immune system
Chemical & physical measures
- Steam sterilization: killing by heat (only in a closed system)
- Nematicides: targeted application, but beware of environmental pollution
Conclusion: Nematode management determines crop success
Not all nematodes are harmful – a balanced soil ecosystem is the key. With regular checks and sustainable control methods, growers can avoid damage and promote beneficial species at the same time.