I had a Christmas cactus at work that I "loaned" to another coworker because she had a better window for it to get the light it needed. Last week, though, she told me that her own Christmas cactus, which mine was sitting by, was totally infested with aphids, so I might want to take my plant back so it didn't get them too. I did take it back and have it outside right now so it doesn't infect any of my other plants. But, I don't see any bugs whatsoever on it. I do, however, see some deposits of white gunk at the joints between leaves and stems. Is this a symptom of aphids, or something else entirely? It reminds me of the problem I had with mealy bugs on my jade plant (http://www.gardenstew.com/viewtopic.php?t=3104&highlight=), though it's not nearly as bad in this plant. Could it be the same thing? If so, I've not been able to kill the mealy bugs on my jade plant using rubbing alcohol, as was recommended, so is there any other way I can help my Christmas cactus? (My jade plant is still alive, but the white stuff keeps coming back every time I treat it.) I will try to post a pic, but my camera is not good at taking photos of such small stuff. Thanks, Zoe
From what I've read powder mildew is a covering on the leaves, not little white clumps at joints. I'm pretty sure it's not powder mildew, since there's nothing on the leaves themselves.