Nepenthes Rotting Smell: Pitcher Decay vs. Root Rot from Standing Water

An Australian grower's new Nepenthes (possibly N. merrilliana) on south balcony has blackening pitchers in winter, rotting smell. Was standing in water (fixed to pebble tray). Expert: smell likely from digesting insects in pitchers. Never let Nepenthes sit in water – causes root rot. Winter pitcher die-back is normal (short days). Cut pitchers only when fully black/brown – green bases still absorb nutrients. Dapple strong sun. Recommends instructional DVDs and caresheets for beginners.