Raspberries

Although my query is about poorly raspberries with possible spur/cane blight, I thought to name the thread just raspberries so that it could cover a multitude of sins.

Right!  I have poorly raspberries.   The web indicates it could be a blight of some sort for which there is no home treatment.   The leaves start with brown/black spots which then get bigger until the whole leaf dies and drops off.  The upper fruit cage raspberries, although a little healthier, also have dark brown splodges on the new growing canes.  Ultimately the web recommends dig up diseases canes and  to desist growing raspberries in that soil, which is rather difficult  as the fruit cages are permanent and the non raspberry areas are filled with other soft fruit.  All that said, the raspberries produced more than sufficient for two of us, with plenty to freeze.  I'm tempted to feed, mulch and cosset the canes in the hope they might continue to produce, notwithstanding the disease, which is basically what I've done for the past couple of years.  Any thoughts anyone?