A reader recently asked us about a tiny translucent worm-like organism she found on her moss plant. She said the specimen is about 3 mm long (1/10 of an inch), and she also sent us a photo so we can see it for ourselves:
We believe this creature is probably a nematode. There are estimated to be about 20,000 species of nematodes present around the world. Some are so tiny that they are invisible to the naked eye, while others are several inches long. They are colorless and don’t have any legs or appendages. So, what exactly is a nematode? It is a roundworm! They are structurally simple organisms that have even been described as “a tube within a tube.” If you look closely, you can even distinguish the two “tubes” that make up the organism in the photo!
While some nematodes are free-living, others are parasitic, relying on plant or insect (and sometimes human) hosts to survive. Free-living nematodes play an important role in the environment by controlling plant diseases, insect pests, and by making nutrients more available to plants. They can have a huge (positive) influence on the health of the soil. So, what role do parasitic nematodes play? Plant-parasitic nematodes damage plant root systems, cause stunted growth and sometimes lead to plant death. A plant that is infected by a nematode will appear yellow, wilted, and/or stunted. Luckily, the most common plant-parasitic nematodes are way smaller than the creature our reader found. Since the nematode our reader found is free-living, we believe it is a beneficial nematode!
To wrap up, today we responded to a reader who found a tiny, translucent worm near her moss plant. We believe this creature is a nematode, which is a roundworm! While there are parasitic nematodes, and even some that infect humans, we believe the one our reader has discovered is harmless.