You say in the past all you've done is powder sugar treatments, and how has that worked out? If it has worked out well, then why look for something else to do?
If you see lots of diarhea looking spots on front of hive and top of lid and on front board, then maybe some fumagillin-b for disentary. Some use crisco grease/sugar patties for trachael mite. Now is a good time for both these treatments.
I've been keeping a few hives for the past 20-25 years, and no longer treatment free as I got tired of the losses.