What the hell is this

session savage

Saw this on a ditch ouside Fethard. The leaves underneath were dying. Its a cobweb of some sort but what made it?? anyone guess??

Alun

See here http://boards.ie/vbulletin/showthread.php?t=2055923121 could be something similar.

ytpe2r5bxkn0c1

Not my field but I think its web of Ermine Moth caterpillars. Mothman will know more.

Mothman

Blaise Howling Percussionist wrote: »

Not my field but I think its web of Ermine Moth caterpillars. Mothman will know more.

Yes, and if my plant identification is right, ie Hawthorn then this is the work of Orchard ermine
http://ukmoths.org.uk/show.php?id=941

The leaves have been consumed by the caterpillars.
It won't kill the hedge but neither will it grow much!

ytpe2r5bxkn0c1

It looked like Hawthorn to me too but my distribution maps don't show us with any Orchid Ermines. Are they under-reported, rare, or new to us? (My books are a bit old!)

Mothman

Blaise Howling Percussionist wrote: »

It looked like Hawthorn to me too but my distribution maps don't show us with any Orchid Ermines. Are they under-reported, rare, or new to us? (My books are a bit old!)

There are a number of species in this genus in Ireland. As adults they are very similar and some can only be reliably identified from the food plant and even then it may not be conclusive. Most moth recording in Ireland is via light traps and the adults are generally ignored.
So for an accurate determination, we need to know the foodplant.....not always easy because there may be none left! or if mixed hedge what is given as foodplant is what is left behind by caterpillars so may be wrong, also the feeding style whether gregarious or individuals, how they pupate, again whether gregarious or as individuals and where they pupate. So there may need to be many pieces of info that need to be drawn together to get a positive ID.

They are micro species and Orchard Ermine is mapped
http://www.mothsireland.com/micro/images/425.gif

The determination where Hawthorn is involved is straight forward because Orchard ermine is the only species that uses this foodplant. Many of the dots in the above map may well be adult records that recorders have made a best guess, so may not be totally accurate, but the impression that the species is reasonably widespread is probably accurate. In general micro species of moths are under recorded

ytpe2r5bxkn0c1

Excellent! That's my something new learnt for today already!

session savage

wow i'm impressed. thanks a million for solving this riddle.....now if you could tell me whats the meaning of life...

QI

Mothman, can you advise on a way to treat this? It has taken over a hawthorn hedge here in Kildare.

Mothman

Afraid not. The caterpillars are at or near pupating, so feeding will stop soon and the hedge will be likely to regenerate

Here is advice from Teagasc advisor which was forwarded to me today. I agree with it all.

They rarely kill the trees and they reflush after the attack has passed. Some older hedges or poor growth hedges can get a secondary infection from other pests/diseases.

There is really no control measures as the infestation will pass as soon as the caterpillars pupate. The use of insecticides over large areas is not advisable as there would be too much collateral damage to beneficial insects.

QI

Thanks for that info. The thing is that the hedge is close to a house and the caterpillars moved from the hedge onto the wall of the house and onto other plants and flowerpots, hence the search for a way to exterminate them.

jwshooter

i cycled past one this eve just outside enniscorthy .it was huge on the ditch.

Durnish

wow, another BBC Springwatch echo.
They had a picture of a worse example of this and were having a competition to guess what was causing the webs.