I have New Zealand flatworms in my garden. They are know to be in the local area and parts of central Scotland have serious infestations of flatworms. I have been in my house for 4 year and noticed a lack of earthworms. In 4 years I've found no worms either in my compost heaps or when digging the veg/flowers beds. The soil is poor but I have been improving it with organic matter. The only earthworms I've found is when recently stripping turf; I've found just one or two in a hour's work. I didn't bother to identify them at the time, they aren't Lumbricus but fairly small and pale (perhaps Aporrectodea caliginosa or Octolasion cyaneum ?).
I read that flatworms can survive up to 2 years without food and that they are thought to only eat earthworms. I also had until recently not found any flatworms (not that I had been systematically looking). This led me to think that I could re-stock the garden, thinking that the flatworm population would be very low. I bought some L. terrestris from here http://www.recycleworks.co.uk/native-earthworms-c-289-pr-16262.html . Just a few weeks later I turned over a plank that had been in my veg plot for a few weeks and found 4 flatworms.
So I'm looking for information on any similar attempts to re-stock. I haven’t found anything in the scientific literature about this - the literature seems to be about measuring impact in farmland (in Scotland and NI); it seems to be late 90s with not a lot after that. I've found info on trying to stop the spread of the pest (DEFRA cods of practice etc.) but nothing useful on small scale control. I know that the only method is trapping and killing and I am now embarking on my own attempts at this (more in future posts).
Specifically I'm interested in any information on...
- methods of control relevant to a small area (I'm trying black plastic on the soil to catch them),
- how successful this may be in terms of control; I appreciate you won't remove them all
- flatworm population dynamics in relation to control and re-stocking
- experiences on the most effective way to introduce earthworms (species, density etc.)
- and the likely outcome of control plus restocking attempt (i.e. is it worth it?!)
I've seen comments in some articles about it being possible to have a reasonable earthworm population with flatworms still present and about deep burrowing worms surviving better alongside flatworms but haven't managed to find any detail on these. Apart from the aesthetics of having earthworms in my garden, my aim was to try and get deep burrowing species into a wet, compacted area of lawn (our football area).
Any help most appreciated.
Useful info. from Dr Brain Boag...
ReplyDeleteUnfortunately I don't think there is much you can do but keep trapping the flatworms and
killing all you find. L. terrestis is particularly susceptible to the flatworm as L. terrestris feeds on the soil surface at night as does the flatworm and L.terrestris take a relatively long time to reproduce compared with some other earthworms. We have some evidence that once the flatworm has eaten out most earthworms they themselves get smaller and numbers decrease which lets earthworms return. This cycle may take 5-7 years we think so there may be hope that some L. terrestris might return but probably not in large numbers.