Patron saints against roaches...

I spent the afternoon practising wrapping wire a cross - I'll put a photo here when I get around to taking one - and have decided to dedicate it to whatever patron saint can best rid of me cockroaches. So far, it's proving remarkably difficult to find the appropriate saint, though...

Saint Magnus of Fussen is a close contender, with responsibility for against caterpillars and vermin. Roaches are definitely vermin...

Saint Gertrude of Nivelles is also a strong possibility, since she deals with mice and rats and fear thereof, and mental illness, and poor people, and accommodation. Many of which are applicable in this case, and roaches are similar to mice and rats...

Maybe I shall dedicate to them jointly. Unless anyone happens to know the proper saint - where are all you Catholics? Isn't this something you get taught as children? If not, why not?!