What is causing my newest growth on my Cattleya dowiana to turn black?

[Alvaro78]

Hello guys!

This summer I purchased a Cattleya dowiana knowing full well they are not easy to take care of. When it arrived it had a new pseudobulb forming and some weeks laters new roots appeared so I decided to repot. After the repot the roots continued to grow so I thought good news. Sadly some days later I noticed that the latest growth had a small black patch at the tip that has since then been increasing in size.

I wanted to know what may have caused it? Does it look like sunburn or maybe it has to do with the watering? Or maybe it is black rot (please no...)? I know dowianas like to dry out between waterings so I have been allowing her to do so.

Also another question if someone knows about this species. Should I now start backing off on the watering and fertilizer to accomodate for the winter ""rest"" she needs? The rest after the info I gathered will consist of no fertilizer and way less waterings.

Thanks a lot!