Sf has a low level of efficacy. These nematodes are very good at preventing infestation and should be used sparingly. However they are pretty shit at controlling an infestation once it becomes established. It's a numbers game. S. feltiae and other endoparasitic nematodes don't reproduce fast enough to keep up.

Bti is a much better control mechanism for fungus gnats once they are established.

[–] Cyber@feddit.uk 6 points 2 months ago (2 children)

I'm new to the concept of nematodes.

What's the general lifespan? I'm guessing you need to keep reapply them after a while ?

[–] Einskjaldi@lemmy.world 3 points 2 months ago

Look at the entire physical world, look at a map of nematodes, it's 1:1. Nematodes are everywhere and are a foundation of life.

[–] Luccus@feddit.org 3 points 2 months ago

As long as they manage to find food and don't dry out, basically forever. My Nepenthes likes constantly slightly moist soil, so the gnats took a liking to it. At some point it got rather annoying, so I applied SF nematodes. Since then I see maybe one gnat per week.

The gnats are not gone, but they now regulate themselves, so they stopped being a problem.

[–] Wahots@pawb.social 2 points 2 months ago

Diatomaceous earth also shreds fungus gnats, and tends to persist in houseplant soil for quite some time Just apply it to soil outside and water it before bringing it in, it's hazardous to breathe in.