Fungus Gnats (Sciarid flies)

[KevL]

These tiny flies form one of the largest group of the order Diptera, and one of the least understood.... Species number many thousands and of those we do know the larvae of which; largely dwell in the soil forming part of the detritivore community within the natural soil ecosystem...Adult flies pose no harm to any of my other plants over the years, i've had them buzzing around everywhere around my pots,... but remember this, if there is nothing there in the soil for them to feed on,...as they would much prefer,...  then yeah if the larvae are hungry and unable to find nourishment they will turn on your roots...

 

but really it shouldn't ever get to that stage, if you've enough rich organics in your soil don't worry about a few pesky fungus gnats.