Raspberry pests - help please!

This is my second year to grow raspberries and I have two problems. First the leaves on 2 of them are dying, looked in a book and can't tell if it's chlorosis or mosaic virus, how do I tell? The plants either side are fine (at the moment). Also lots of my healthy plants have some sort of bug on them. They're v v small so not sure if they're a fly but I think not. If they are on a leaf there's loads of them and they are a greyish white colour. Anyone know what they are and how to treat them. I'm wary of bug sprays as we are harvesting the fruit and I don't wash raspberries normally. Any help gratefully received :cnfs: