Blackcurrant - unidentified problem

[vivienz]

I have 5 ben sarek blackcurrant bushes on my plot, now coming up to 3 years old. They are only about 2 ft high and the same diameter.
I snipped a couple of crossing branches off today, only to find that the centre of the branch is hollowed out and black. On some branches, it goes right down to the trunk, and yet does not go as high as the tip of the branch. One I have in front of me has the problem, but it stops about 6 inches from the tip. The branches outwardly appear healthy - not withered and producing buds that are starting to open. I've looked in Dr Hessayon and the most likely culprit appears to be the grubs of clearwing moth, but he indicates that the stems wither and die, but mine haven't.
I'm in a bit of a quandry as to what to do - if it's a bug, I may persevere with the plants, but if it's a disease I'd rather be rid of them as soon as possible.
Hmm - any ideas anyone?

[oldherbaceous]

Dear Vivienz, i agree about the problem being clearwing moths.

But i thought the damaged stems often survive.

A good way of telling which stems are infected, is to give them a slight bend and the infected ones will normally snap.
Make sure you burn any inected stems.

Lets hope the bushes are not to badly infected.

[vivienz]

Thanks, OH. Having only spotted this not long before I came home this afternoon, I'll have to wait for further investigation next week, but I shall deal with it ruthlessly!!! Well, not too ruthlessly, or I'll have no branches left. Thanks for the tip on spotting which are the bad'uns.
Vivien