what is eating my dahliah plants - leaves and flowers
By Brownie
Essex,
United Kingdom 
The dahliah is called 'Bishop of Llandaff' and I have watched the first flower bud which opened today and all the petals have been eaten. I have been spraying the plant for weeks when I noticed the leaves being eaten but cannot see any bugs - only small black specks, which look too small to do the damage.
10 Jul, 2009
Answers
Could it be earwigs as they tend to like petals of lots of flowers ? You may have to go out with a torch and see if you can catch anything 'red handed'.
An earwig trap left overnight of a yoghurt pot, stuffed with straw or dried grass and upended on a cane the same height as the flowers may reveal them in the morning.
10 Jul, 2009
I was thinking earwigs too. the small black things might be thrips. they suck sap and the leaves and buds open distorted. they are only around for a short time so are not too much of a problem.
10 Jul, 2009
Oh how disappointing. But it'll be okay I expect - the little black specks you refer to might be blackfly I suppose. However, after the recent rain, there are an enormous number of very active snails and slugs about at night - have you tried slug pellets?
10 Jul, 2009