When it germinates
Wet tissue
spores need a wet surface and about 55 to 70 F (13 to 21 C) to start
Dew
that wetness can form even in otherwise dry weather
After start
growth can continue across a wide humidity range, but high humidity and cool air help it
Wounds
pest damage, pruning cuts, and dying tissue are easy entry points
What you see
Color
starts whitish like mildew, then turns smoky gray or brown and fuzzy
Flower
late, dense buds can go slimy brown in high humidity
Stem
unhealed breaks can become cankers that starve the top of water and feed
Shade
dim, crowded, or crevice-heavy spots usually show first
Prevention
RH
Aromaindoors, keep humidity under 50%
Water
Aromairrigate with lights on, and have leaves and buds dry before lights-off
Sanitation
Aromastrip dead tissue and sterilize pruners between cuts
Outdoors
AromaBacillus subtilis sprays (Serenade is named) are listed as a preventative
Barrier
If it is already in the bud
Care
Aromapoking at rot can spread spores
Tools
Aromadip blades in alcohol or hydrogen peroxide after each bud you clean
Late flower
Aromaremoval is hardest once flowers are dense