Huge ichneumon wasp

[peterbolson]

I was amazed to find this in my house today. Body about 30mm long and ovipositor at least another 50mm. Looks as if it could be Rhyssa persuasoria but according to my book this is found in pinewoods & predates on horntail larvae, also to be found in pinewoods. I have a few large conifers in my garden but there are no pinewoods in the vicinity.

[Dogghound]

Its Rhyssa persuasoria a very distinctive species. Do you have any new pinewood products? if not then im sure there are pine woods not to far away large insects can travel large distances, plenty of suitable pinewoodland in cumbria.

[James M]

That's an impressive beasty! it must be big if it predates on horntail larvae

[peterbolson]

Thanks Doggwood.
No I don't have any new pine products ! Should I take it to the nearest pinewood to release it or just let it go in the garden ?

[Gerel]

We get a lot of both Rhyssa and horntails here in spruce and larch plantations and I've photographed both ovipositing in larch logs. Neither seem to be dependent on pine per se.

Steve

[Cole]

Having read the prevous postings I'm starting to worry. I have seen one of these insects in our garden two weeks ago. The only pine trees in the neighbourhood are lolandii. However I have a new garage which is clad in siberian larch. Can these blighters do any damage to timber?

[Gerel]

The ichneumon in the original post doesn't harm timber at all, in fact it lays its eggs on the larvae of a sawfly commonly called a woodwasp or horntail. Its grubs then eat the horntail larvae, which do eat wood. So the ichneumon is actually a beneficial beastie (horntail grubs on the other hand will chew holes the width of a pencil in untreated softwood)

[Dogghound]

Originally Posted by peterbolson

Thanks Doggwood.
No I don't have any new pine products ! Should I take it to the nearest pinewood to release it or just let it go in the garden ?

Im sure you will have done so by now, but I would just release it in you garden.