As a mycologist, I wanted to make sure that the latest fungal research gets in front of the bee keeping community.
Bees have been found to seek out several species of wood-rotting fungi. They have been seen sipping from the sugar-rich fungal roots.
A preliminary study showed that access to these fungi substantially reduced bees viral load.
One of the theories of CCD, Colony Collapse Disorder, is that farming use of anti-fungals has reduced the availability of these beneficial fungi.
This is still being studied, it's not peer reviewed, and it's not conclusive, but I feel it's important enough for the bee community to know about it.
These are known species of fungi that bees seek out:
Ararikon, laricifomes officinalis
Tinder Polypore, fomes fomentarius
Red Belted Polypore, fomitopsis pinicola
Garden Giant, stropharia rugosoannulata
Turkey Tail, trametes versicolor
Chaga, inonotus obliquus
Red Reishi, gandoderma lucidum
Red Reishi, gandoderma resinaceum
They grow on willow, birch, and fir, although the Garden Giant will grow with corn.
These fungi are assumed to help the bees through their anti-viral properties and thus contribute to their general well being.
I haven't found any bee supply companies offering these fungi.
I have found a couple of fungi supply companies that sell Mushroom Growing Kits for many of these species, but not all of them.
The growing kits are just rotting wood, easy enough, and bees will find them on their own when they want them.
My goal is to help stop CCD, and if fungi can help with that, wonderful!
I hope this helps.