white fuzz on Daylily tops
 

I have been getting a dense white fuzz on the tops of my daylilies for
the past 2 years. The fuzz is mostly on the very tip of the plant as
it is trying to form buds.

Recently I have noticed the fuzz starting to show on the very edges of
the leaves below the tops of the plants as a very thin line.

The fuzz is only affecting one group of plants and not any others.

I'm up in zone 3 (Winnipeg, Manitoba) and the plant has done well in
the past.

I don't see any insect activity. Keeping the fuzz wet with plain water
seems to slow it down a bit.

It can get so bad the buds won't form.

HELP!!