Ask the Expert: what is the cottony/cob webby build up? I have a Anthirium I have had it for a few monthes and it has been doing fantastic until i discovered That i was over watering it. I have now cut down on watering it and have been keeping a very close eye on it and it seems as though over night it has some sort of web like build up in the almost dead bloom. I guess it might be dust but it really doesn't look like it and for it to build up that fast, I just want to know if this is normal, if i should remove it, or cut the bloom off altogether. Tiffany Reply: I am attaching pictures to help with identification. If it looks like the first picture (from Arizona Cooperative Extension) which is cottony cushion scale, you will need an insecticide that is safe for houseplants. Your local garden center should have Fetilome whitefly & mealbug killer for houseplant - or at least something similar. The second photo (from CSU/Denver County Extension [...]