My package bees have not yet built out their second deep of comb. The first was built very quickly, but since then the girls have been reluctant to build more. I can think of a couple of theories, the main one being that there was a shortage of labor. They stopped as the population of package bees was beginning to decline sharply, before the new brood started to hatch out - maybe most of the bees were needed to cover brood or forage and they didn't feel pressed to build more comb. Theory number two is that there was insufficient nectar flow and it was all being used to make bee bread.
I took the question to my local beek listserv and they advised me to continue feeding sugar syrup until the second deep was mostly drawn, and that it wouldn't hurt the colony even if they were wrong. This is a side issue, just to explain why I'm still feeding during flow.
The bees continue to take syrup from my top feeder, but are eating pretty slowly. They still haven't built much wax in the second deep, but have 3 frames of capped syrup and or honey and another frame open in the bottom deep. However, it's been hot and humid here lately, and humid in particular with rain at least once a day in my area.
Because of the way a top feeder goes on the hive, when it's on the inner cover is completely inaccessible to the bees. In the last couple of weeks I have seen an increase in mildew on the bottom of the inner cover, and this week I started to see greenish mold. There's only a little mold on the top of the inner cover, so I'm guessing that it's the result of being directly over a pool of sugar water for weeks in 94 degree hive temperatures.
My main question is: will this mold/mildew harm the bees in any way? Question 2 is: will the bees clean the cover and stop further mold if I remove the feeder so the bees can access both sides of the inner cover?