The white flakes could be from aphids or another type of parasite. Examine the plants closely and look for tiny webbing on the undersides of the leaves, especially the ivy plant. You can make a mixture of 1part rubbing alcohol to 10parts water, mix in a spray bottle, and spray the plants daily. This will get rid of any aphid problem you have. If this doesn't work, you might have some time of fungus problem.
