Hello: I am trying to identify a foliage problem on a stand of Raspberries. Two plants along a run of 15 plants are affected by this condition. The remainder of the row is not affected. It could be a magnesium or other deficiency, but not sure, so am checking with you. Description: Leaves have a brownish blotches along all areas between the veins. The veins are dark green. The leaf margins are drying and curled. The growth at the tops of the canes are more effected than the growth at the base. There does not appear to be an insect problem, at least nothing visible. I have attach photos. An recommendation on what this is and how to treat would be most welcome. Many thanks,
