I am taking the liberty to leave a comment too, as I have a border of raspberries myself… Maybe your manure was “too fresh” or have you watered them too much ? Or maybe your raspberries didn’t have strong enough roots ? Also, raspberry plants need to “breathe” at the bottom of the stem.
Before you buy some more : raspberries produce numerous shoots, perhaps will you be able to re-use them next spring !!
