Posted: 14/02/2012 at 16:35
New Zealand flatworms are here to stay unfortunately. They have become widespread throughout the British Isles and there is no treatment that I know of. They live underground chasing along the earthworm tunnels which can go quite deep. The only thing to do is to manage them by capture and kill methods and encourage predatory beetles as stated in the article and above comments. Their egg sacks are shiney black balls that harbour a number of young ones so they need to be disposed of as well. Encouraging earthworm to reproduce more with plenty of manure and compost helps to achieve an equilibrium of sorts but vigilance is always needed.