What is the culprit?
I was happy to see a healthy new basal shoot on my Altissimo climber, until one day I went out and saw that this had happened to it:
What kind of pest does this? I'd noticed a couple of cut off basal shoots on other roses that had more robust growth so I didn't pay as much attention. Although the ones I saw before looked more like they had just been cut off, not hollowed out.