Question

Small Worm   I've been searching the internet and posting on forums regarding the small (about 1/4 inch long), white worms that I've been seeing in the water trays of a few of my plants for months now.  So far, I've gotten nowhere!  This is my last attempt at potentially finding out what they are, if they're harmful, and what to do about them.

They're quite a mystery to me as all of my plants have their own private water trays.  Also, all three of the affected pots came from different vendors.  Two of the three were shipped potted while the other was shipped bare root.  Two of the affected pots are in a terrarium type setting, while the third is in a windowsill in a different room of the house.  The only thing I can think of that has been consistent for all is the water that I use.  I buy gallon jugs of distilled water, so that can't be where they came from either...

The first pot that I noticed to be infected was that of my Pinguicula Esseriana.  The only reason I discovered the worms is because of an outbreak of what I assume to be spring tails (confined to this pot alone).  When I was trying to eradicate them, as I did not know what they were at the time, I noticed the worms.  One of the plants turned brown and sort of fell apart months before the spring tail infestation and now I'm wondering if perhaps the worms were responsible but I hadn't noticed.  I grow my Pinguicula in 100% MVP Turface.  My Heliamphora minor, which I have also found to be infected, was shipped potted in dead long fiber sphagnum moss.  The third and final infected pot contains Drosera Scorpioides which were shipped potted in some sort of peat/perlite mix.  

So far I've tried mosquito dunks and Orthene to kill the worms.  After the mosquito dunks failed, I was a little frustrated and uprooted all of my P. Esseriana and soaked them in a strong solution of distilled water and Orthene powder (for a couple of hours).  There were a bunch of dead worms in the bottom of the container after this treatment.  All but one of the plants died from this, but at this point I might be willing to sacrifice my poor plants just to be rid of these gross little creatures.

If you have any idea of what these are, or have had any experience with them before I would be very thankful for any advice you can offer.

Answer
They are likely a type of nematodes.  There are beneficial nematodes that eat other pests, and there are types that eat plant roots.  Without knowing what type they are, you should assume they're the ones that eat plant roots and get rid of them.

Mosquito dunks are ineffective against nematodes.  They only work on fungus gnat larvae and mosquito larvae.  They may potentially work on spring tail larvae too, but I haven't read any reports about that.

Orthene is a systemic insecticide, so it's not at all necessary to soak your plants for several hours.  You can simply spray the plants.  The plants will then absorb the insecticide into its leaves and roots.  When the nematodes eat the roots, they will ingest the insecticide.  

At this point, you have already taken the steps to eradicate them.  The common treatment is to unpot your plants, rinse them completely, spray them with a systemic insecticide, and repot them in fresh, clean soil.  With plants that have very delicate roots, such as Drosera scorpiodes and other pygmy sundews, it's best to simply dispose of the plant and pot.  They are unlikely to survive the harsh treatment necessary to eradicate the nematodes.

Keep these plants isolated from other plants until you are certain the nematodes are completely gone.  Also monitor your other plants and be prepared to treat them immediately if you see any signs of nematodes popping up.  

Good growing!
Jacob Farin