mildew in hive

[Alicia]

Hi all. Its been very rainy with temps 40-55 degrees. Inspected hive today and found mildew on inside of of top cover. Colony below looks great and no sign of mildew there.
What should I clean with and how do I prevent more?
Thanks!

 

[Latestarter]

What I would do is buy a new outer cover and replace the one with mildew. Then do a 50:50 bleach and water spray down of the bad cover and set it aside to dry and for use later when the new one gets mildew-y

 

[babsbag]

Agree with @Latestarter. I think that prevention is going to be ventilation. You need to leave the lid ajar or some people drill a 1" hole in the side of the top box and cover them with screen. You need the ventilation so you don't get condensation too. Condensation can drip back on the brood nest and chill them. Telescoping covers are nice but much harder to vent a corner of it than the flat covers they use commercially. I have both, like the flat ones better.

 

[Alicia]

Great, thanks. I will look into a new cover and sstart cleaning. Also will look into the flat cover.
Appreciate the help.

 

[Latestarter]

Another way to add ventilation is to add a 1/2" high piece of wood under both front corners of the outer cover reaching from the outside ends to within about an inch of center. Like this|========XXX=======| You want to leave an opening maybe 1-2 inches long at the center point. With the back of the cover all the way down, it will leave a gradually increasing opening on either side as well as the 2" opening at the front. You want to keep the front opening small as it will need to be defended by the bees to prevent robbing.

Edit: It wouldn't let me show the opening to scale, so;
| is the side of the box
= is the 1/2" high stick
XXX is the 2" opening in the center

 

[Alicia]

Update. ..got the mildew all cleaned out. Bees look great, busy. Comb looks uniform and full.
Thanks for the help and support!