This is an older thread, yet useful to me as I have a red aphid infestation on my Mandevilla vine brought indoors for the winter.
I brought this plant indoors after soaking soil and treating with Neem. Regardless of preventative measures, still prone to red aphids indoors. I'm now using an organic insecticidal spray (Castile soap, a touch of vinegar, minced garlic) and will report back. Neem and DEarth did nothing to stop the infestation.
