The pitchers on one pot of S.flava that I have have grown to about 6 inches and then turned black and died from the top down.

What could have caused this? There's another pot of S.flava right next to the affected pot in my greenhouse growing fine. I can't see any obvious signs of insect attack and the plant is throwing up new pitchers.

I get deformed pitchers from time to time on some of my Sarra's and just put it down to rapid changes in conditions in Sunny NW England. Iv'e not seen anything quite like this though.