I am sorry for this delayed reply to your gardening question. We are transitioning to a new Q&A system and your question was unfortunately lost in the transition. I have discovered it now and hope this reply is not too late to be of help.
Your description of the white stuff on the foliage sounds like powdery mildew although Eugenia is not on my list of powdery mildew susceptible plants. It may be that the white material is the reside left when irrigation water dries on the foliage. This is not a concern although drip irrigation is a better way to water.
The rusty spots are most likely a fungal disease. You could try a spray of chlorothalonil (Daconil) as a best guess approach or better yet take a sample from the plant to your local County Extension Office to see if they can identify the problem more specifically and recommend an appropriate control product.
Thanks for the question. Please stop in again soon!
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