Ben Blackmore wrote:
Just went out and checked on the raspberry leaves, I don't think its a
virus, all the new leaves growing at the top are dark green, so they seem
ok, its just the leaves around the base.
If it was a virus surely it would spread to the new top leaves. I guess it
could be a fungle thing, or maybe just overwatering.

Ben,

One other thing to consider, is that if this raspberry bush is a summer
fruiting raspberry, it will be thinking about putting up new shoots for
next years crop, and this years canes will be thinking about dying back.

Canes in my garden that have been mostly cropped, are starting to look
really tatty. I have healthy new baby canes growing well, and will strat
tying these in when they are large enough, and cut the old ones out when
the crop is finished.

If I were you, I'd improve an area of ground in the autumn with a mass of
well rotted horse manure, garden compost and maybe a bit of sand or gravel
if your clay is really heavy, and transplant all your raspberry roots very
carefully into the new area about a month later.

If you can't move your raspberries, do them a favour and give them a deep
mulch of manure.

No need to feed them after that - I don't - just once a year with manure.

If your raspberry is an autumn fruiting variety, yellow leaves are a
problem, and could also be the sign of a nutrient deficency - e.g.
magnesium. My autumn raspberrys are a nice bright green colour and growing
fast ATM.

HTH, Sarah
(Gardening in heavy soil with clay underneath in extreme N.E. Wales)