This is a first for me...Anyone have any experience with a black mould forming on their Neps?
If so what is the cause? Too wet? Something to do with excess nectar?
I recently went from a timed spray system to a misting system with artificial leaf balance-arm. The result is higher humidity and SOME plants being wet more often.
At about the same time I notice that my large green N. maxima (not directly misted) got quite a covering of this black mould on it's pitchers and a few spots on the leaves. It also appears on a few other plants (mostly on the older pitchers too).
It's a black dusty kind of mould that runs off easily. It is mostly formed on the outside of the pitchers, peristome and a few spots on the leaves.
The odd thing is that it does not appear to be on the plants that get most of the direct misting!?
It does not appear to be causing any damage but is quite unsightly and I'd like it gone if possible.
I have seen it once before on some of the older pitchers of my N. ventricos but it only lasted a short time and then disappeared.
I'll get a pic ASAP if it helps.
this black mould grows on nectar secretions of the plants under high humidity, low temperatures and low light. I normally have this problem only during winter, it disappears in spring under higher light levels and temperatures. The plants aren't affected by this mould.
Must be the increased humidity that's done it as day length is increasing and we've had a few weeks of great sunny weather (not like the first 2/3 of Winter) so day temps are up as well.
It looks shocking on the all green N. maxima!
Sooty moulds are quite harmless but can be very unsightly. They are associated with copious nectar production, and in some plants may indicate the presence of ants & aphids.
Your observations coincide with mine. This condition does seem to affect some spp. more than others under identical conditions. Unlike Joachim, I have seen it spread fairly rapidly on pitchers grown in full sun, outside with plenty of ventilation. The sp. that seems most vulnerable for me is N. faizaliana . Any sp. with lots of nectaries on the tendrils and pitchers will need to be watched closely for its development. I have found that a very light "wash" of dilute Physan on a cotton swab returns my carbon-coated pitchers to "just-like-new" condition. I have also found that benomyl gives good pre-emptive control, but it's no longer labelled for greenhouse crops in the U.S., so you may need to try its replacement - carefully!