I'm not sure how much of the turning black is due to rotting and how much is due to bacterial or fungal issues. Some of mine do, too. If they begin to shrivel, it seems the kiss of death. I won't use any chemicals on them, or anything else in the garden as everyone in the house is very allergic to chemicals and there are dogs and a cat, not to mention many birds in the garden.

It would be interesting seeing if a smaller plastic water bottle could suffice in place of the pop bottles to prevent evaporation. Or, could you tape a plastic bag over that one foam cup?

As I've said, each climate and micro climate is different. We have to each explore and experiment to see what's going to work for us then share it in hopes of finding something standardized. I've had NO luck covering any of the cuttings here. Too hot, too brilliant sun and too humid at this time (AWFUL for "the desert").

I don't know of the ones which shrivel and eventually turn black are doing so due to botrytis or what. Once it starts, though, they're goners. Kim

I don't spray much, either. Partly the warning lables on insecticides scare me, partly "lack of opportunity" i.e. laziness, and mostly because my sprayer has been broken for three years now. Nothing important has died, you know, and I've discoved there are a decent number of roses that grow without any spraying. I get alot of weeding done instead!

Humm, I do have some water bottles that would fit nicely on the cups. I didn't think about that. I think the Bella Donnas are goners, too. It's almost dark. I'm going to put out the water bottles!