By Lesp
Leicestershire,
United Kingdom 
As a "newbie" to this site forgive me if this subject has been asked before: We have successfully grown Fuschias of all types for many years now, almost every year without any problem bugs or diseases, but in the last week we've found that two or three only of our plants are being eaten by the caterpillar(?) in the photo. It's really small, about 2 to 5 millimetres, green with a black head, and appears to have legs on the front segments. It eats the undersides only of the leaves, resulting in the leaves dropping, and it's activities now appears to be affecting the flowers on one plant. No other plants in the garden are affected.
I assume it's from a moth (?) but what species? Strong solution of Fary Liquid kills them, and we've also sprayed with Pravado.
Anyone have any solid identification please?
28 Jul, 2010
Answers
Hi Lesp,
These are undoubtedly new, hatchling caterpillars, either from a moth or a Sawfly species. They will shed their skins (and increase in size) 5 or 6 times before reaching maturity.
There are a number of species that will use Fuchsia as a food-plant - the Black-lyre Leafroller Moth is one of the most frequently seen, but there's no way of ID'ing them at this size & age as they have no distinguishing characteristics as yet.
The spectacular Elephant Hawk-Moth is another well known Fuchsia muncher, but I would doubt that these belong to that species as they don't typically lay large quantities of eggs together in this way.
Although washing-up liquid is certainly effective at killing a variety of insect pests I would strongly advise against using fairy liquid or anything petro-chemical based since they can do serious harm to the soil micro-organisms and do not readily or quickly break down in the environment. A vegetable-based soap or washing-up liquid (like Ecover etc.) will do the same job without the damaging side-effects.
You can also use a variety of vegetable-based sprays (either home-brewed or shop-bought) made from the likes of Chilli, Garlic & Rhubarb, which all act as powerful natural insecticides.
29 Jul, 2010
Thanks to both Ian and Ilex for these answers. I'm especially interested in your answer Ilex as it begins to narrow down the search for the "Mother" culprit. Whilst I agree about Fairy, we were advised that others don't have the same effect, and I must admit there was a degree of panic setting in, seeing the leaves disappear!
Many thanks again though to both of you.
29 Jul, 2010
Firstly Lesp, Welcome to GoY. It doesn't matter if a question has been asked before, if you don't know the answer then you need one and by the look of your photo you need one faster than you can trawl through the thousands of questions already asked!
I can't tell you what the bug is but I do think you are tackling the problem the right way and the only other thing I can think to add is to rub the caterpillars off with your fingers. (Use those plastic gloves you get at petrol stations if you don't fancy touching them yourself!)
29 Jul, 2010