Those Bl**dy Caterpillars again

[Kepouros]

Once again the irises in the ponds have finished flowering, and immediately on cue the caterpillars have appeared and within 2 or 3 days have reduced a large number of leaves to skeletons.  Every year they appear - little grey things about an inch long - in their thousands (I counted 84 on one leaf), demolish most of the iris foliage, then disappear.  Scrape a few off into the water, and it boils with frantic carp and orfe pretending they`ve never seen food before, but this is far too time consuming a task to clear them all.  I never find any chrysalises to indicate what has happened to them, so presumably once they have eaten the iris leaves they return to the water, but I have never noticed any particular abundance of strange lepidoptera emerging from the depths.

So can someone PLEASE tell me what on earth they are, and where do they go after they`ve eaten my irises down to the water level.

[Kepouros]

[shirlton]

We grow irises all around the pool and have never seen any caterpillars

[Kepouros]

Would you like me to send you some?

[Georgie]

Once again the irises in the ponds have finished flowering, and immediately on cue the caterpillars have appeared and within 2 or 3 days have reduced a large number of leaves to skeletons.  Every year they appear - little grey things about an inch long - in their thousands (I counted 84 on one leaf), demolish most of the iris foliage, then disappear.  Scrape a few off into the water, and it boils with frantic carp and orfe pretending they`ve never seen food before, but this is far too time consuming a task to clear them all.  I never find any chrysalises to indicate what has happened to them, so presumably once they have eaten the iris leaves they return to the water, but I have never noticed any particular abundance of strange lepidoptera emerging from the depths.

So can someone PLEASE tell me what on earth they are, and where do they go after they`ve eaten my irises down to the water level.

It sounds like Iris sawfly caterpillar.  Is this it?

http://www.lincsbirder.co.uk/iris_sawfly.htm

G x

[Kepouros]

Bullseye Georgie.  I`ve looked it up and found pictures of Iris leaves looking every bit as bad as mine.  Seems I`m lucky though in that mine don`t appear until flowering is finishing, whereas in  other areas they actually eat the flowering stalks as well.

Many thanks