Wilting raspberry canes

Wonder if anyone can shed any light on this.

I noticed that since my last year's raspberry canes started growing buds, the canes have started to wilt.

I've been doing some research and it seems there are a lot of reasons for wilt, most commonly cane borer. However the canes show no sign of this damage. Also it's not just the tip that's wilty, it's the entire cane.

However, the fresh green growth is absolutely unaffected. It's very lush and vigorous.

What could be causing wilty issues on the old growth and not the new? Surely anything would affect the entire plant. The differentiation between old canes and green canes is very obvious in this picture:

 

look fine to me I think its the way you are growing them ... you need to cut out the weak shoots/canes and tie the main/stronger strong stems in

I havnt seen growing on a wigwam before ? raspberry without training will flop over just like a blackberry bush does when growing in the wild

 

It's not quite a wigwam, really just three canes and I popped them in to try and give me points to tie in! So you reckon just tie a raspberry cane to a bamboo cane 1:1 ? I can certainly do that. They do seem to be growing berries but were just looking a bit limp which concerned me.

 

Hi I would put canes in the 4 corners then tie string around and cross to give them support but you need to cut out the weak shoots from just under the soil this will help put energy in to the stronger shoots

 

Not sure, but I would suggest some kind of mineral deficiency.

I dont think there is any wilting going on, the growth looks normal to me apart from the lower leaves looking reddish and pale.

 

Hmm they're definitely wilting. But perhaps not so much. The leaves are sort of... flaccid... for want of a better word. But they don't seem to be wilting extremely fast so maybe there is life yet left.

I have done as instructed and removed the canes. I've put in two canes and strung twine across them for the canes to rest on and managed to get them looking a bit better. I pruned some of the suckers. There were only 6, so I cut off the two weaker ones and left 4 for next season.

Feeding is probably the answer. I will get something in town.

 

I'd try a one off sequested iron feed first, it should green up the foliage.
Then for the rest of the season just a balanced feed should be ok.