In article , pied piper
writes

It deters the worm from surfacing thus leaving no casts and worms burrow
both vertically and horizontally.

The reason the worm surfaces is because it feeds on the surface. If you
deter it from surfacing you deprive it of its food source. Can you
therefore explain why the worm is going to remain burrowing in the area
where you have applied the substance?
--
Kay
"Do not insult the crocodile until you have crossed the river"