caterpillars - arrghhhhhhhhhhh!!

Trucker

Are these brown tail moth caterpillars or something else?  They shredded my rhodedendron last year and its just starting to recover.  But I can see lots of these caterpillars just appearing again

 

.  Only 2-4mm long at the moment.  How can I get rid of them? (aside from picking them off?  Anything I can spray on them?

Dovefromabove

I think these are Vapourer Moth caterpillars  - there's some info here 

http://www.wildaboutbritain.co.uk/forums/eggs-larvae-and-caterpillars/30134-vapourer-moth-caterpillar-what-does-eat.html