Sometimes when floricanes are near the end, the leaves turn. It kinda looks like that to me. Nothing to worry about. The reason i think this may be the case is the veins look very good. If this is a primocane, then you do have something wrong.

You may have been hoping for more people responding. Drew is a very good berry guy, so take comfort in his answer.

I have red raspberries, but have never had any trouble with them. The leaves lower down turn yellow but I have not paid any attention to the subtleties.

I have given away plants that grew outside the designated area and those have gone into some bad situations. In one case they were being trampled and peed on by dogs for a year and a half before the own put a fence around them. this year they look very good. So don't worry too much and don't put any chemical fertilizer on them.

Let us know if any change. if you think it could be a deficiency the best way is a soil sample to your local extension, and tell them you want to grow raspberries. they will tell you what you need.
If you want to just cover all bases. use Holly Tone or any complete balanced organic fertilizer. Dr Earth is also excellent. Many exist. You could add azomite, rock phosphate, also use kelp. This will supply all trace minerals and such. Iron is good too, like Iron-Tone.

In the photo I see a small leaf with tip burn. That is usually too much nitrogen. Possible you have a leaf spot of some kind. If not many leaves are like this remove them. You can use copper, sulfur, lime sulfur as a preventative. All organic fungicides.
I don't have any fungal problems here, but do use a preventative, as I need it for fruit trees, I hit the brambles while I'm spraying the trees.Usually early in the season before any flowers or berries. I use nothing once flowers form.

Sorta reminds me of damage that a piercing - sucking insect would do like aphids or Brown Marmorated Stink Bug. Both critters may be in you area, do some scouting.

As far as nutrition goes, what are the leaf positions that have those symptoms, near the shoots, down low, I can't really tell? You're growing in containers, yes, what's the growing medium and what are you using for fertilizer, how often is it applied?

I see more than one thing going on depending on the leaf from green and healthy to one in the background with yellowing, necrotic margins to the one with stippling.

Thanks for the replies folks. This is the first year that I am growing raspberries (actually, the first year gardening :). The spotted yellowing is occurring on the lower portions of the first year stems, hence my great concern. I have sprayed them with an organic copper fungicide, and hoping for the best.

The growing medium is soil. The container rim in the picture is just for show purposes. I added 50/50 % top soil and garden compost when I dug the hole. I haven't added fertilizer after that as I felt the compost should last for some time.

The sickly leaves in the back of the picture are on the second year stems. The plant was in bad shape at the nursery when I bought it. None of the flower buds matured into berries ( btw, is this expected on new raspberry plants? ). But the new canes are growing very well, except for the spotted yellowing on the bottom leaves on these canes.

It doesn't look like typical leaf spot, it could be mites. Any spider webs? Look on underside of leaf. Anything there? Take a photo if you see anything. Little red dots etc.