>> How can a nectar dearth be predicted, indicated?
A nectar dearth is hard to predict, but can be detected with occasional observation and inspection of the hive. One indicator is long periods w/o rain. In such situations flowers will bloom and produce pollen but due to low water availability in the soil there will be little to no nectar produced.
>>I have some honey (that is not for human consuption) that I extracted from hive body frames to help solve a honeybound situation and may have some medications in it. I would like to use this honey to feed back as nectar and keep my queens laying eggs as long as possible. Is it possible to dilute honey with water for this purpose or do I have to purchase more sugar to make a nectar substitute.
Dilute the honey with warm water, mixing well. Honey diluted by about 50% water can be fed back to the bees the same as sugar syrup.
>>Also, I now have wax moths. Is this a problem that requires intervention on my part or is it something that a growing hive will solve on their own? Will the cold winter temperatures kill the wax moths and worms? I could then clean up the mess left behind in the early spring, over 50% of my frames are plastic so this should help.
Wax moths usually can be cleaned out by a strong hive. However, once they are pervasive the best solution is to cutout the combs and replace the wax with foundation. When using plastic frames I would suggest removing the wax, melting it, strain it, and reapply the wax to the sufface of the plastic thereby renewing the frames.
Switch to screened bottom boards if you're not already using them. The larva of the wax moth (and varroa mites too) when dislodged from the comb will fall through the bottom and out of the hive helping the bees correct the problem.
Oh, and welcome to the forum.