Summer bedding plants infection

Hi Jean, this is just a bit of a guess really but i have had simular problems with pertunia and geraniums.not so much that they have completely died. but because of the warm wet weather recently a lot of the flowers have rotted before opening on the geraniums and a bit of mould and pest problems underneath. and the pertunia have been very leggy and got eaten by slugs. which i think is all symtomatic of the 'wash out' summer we have been having. maybe the same is true of your Busy Lizzies. the one thing that they all have in common is they do like quite dry and warm conditions, particually around the base and inside the canope of the plant. most of my geraniums are in pots so i have mulched with gravel, and put a couple of inches of gravel in the bottom of the pots, to increase dranage, which seems to be helping, as they are not sitting in damp soil all the time. but the pertuninas well i have just had to suffer the loss, as they are in the beds and i don't really want gravel everywhere in the beds. and i have replaced with viola. if you are able, maybe try adding some gravel to the base i have done this with my daughters busy lizzy (we only have the one this year - and it is in a pot) and it does seem to be thriving. good luck, hope this helps