Poor spider!
If he's there, he's finding something to eat.
There's a very good chance he's your best friend in that room.
What is a "milk treatment"?
Without knowing, I'll mention that milk can bring a variety of molds into the picture, as well as a nasty smell.
If this is a common practice, could you direct me to info?
Thanks!
I took a look around and found out what's up.
I use a teaspoon of baking soda in a quart of water. I soak the plant with the solution.
This leaves a visible dusting of soda crystals on the leaves, but the powdery mildew should go away.
The baking soda shifts the pH on the leaf surface out of the range that powdery mildew can reproduce.
After a couple days, spray the plants with clear water. Repeat weekly until there is no evidence of mildew.
The other solution I'm familiar with is sulfur burners in sealed grow situations.
Sulfur creates a mildly acidic condition on leaf surfaces, shifting leaf pH in the other direction.