I've been out and checked mine, nothing untoward there.
I wonder if it's a caterpillar .... don't really know.
In any event, i'd spray with Provado, it's a wonder :-)))

Thanks Louise, I've never had a problem before with geraniums, one of the reasons I like them so much. This has devastated the leaves all summer although the plants have grown very large, they looked awful. I have searched manically over the season and not seen any sign of pests. They were both moved last year and planted in new topsoil so I did wonder if there was anything in the topsoil, but everything else is growing well. I don't really like to use sprays etc. Is Provado the vine weevil one? If so, I did buy compost with it in once and it worked...no vine weevil, but I've just ordered some nematodes for them which I've used before. If the problem exists next year I'll have to do something, it wasn't worth growing them:-(

Provado is the all purpose one, it'll get rid of most unwanteds !!!

this damage is typical of sap sucking insects, leaf hoppers, aphids etc. as to the actual culprit not sure.

Does Provado work for root mealy bug?

Thanks all, SBG, do leaf hoppers etc specialise in geraniums? I can't tell you the damage they caused even deformed flowers..is that possible with just insect infestation?:-)