Needless to say, this repellent has weaknesses.
One weakness is the increase of dead bodies caused by continuous reproduction of yukkuri larvae.
Another weak point is there are concerns for the cost of yukkurin manufacturing.
In the first place, this repellent is for "houses where pet yukkuri(s) live, yet also flooded with house yukkuris", which means if this strict condition is not met, it doesn't work at all.
And the factory couldn't think of a way to overcome such weaknesses. ...surprisingly though, this weak point has been considered something that can bring a merit.A merit that makes the factory think that doing large-scale confirmatory experiments in yu-zones on purpose is worthwhile.