I tried the milk route.
1 it stinks like rotten milk
2 it leaves behind a milky/powdery residue. Which, is similar to the wpm.
3 it didn’t eradicate the wpm.
There’s an ongoing thread about wpm here.
But the short version is—- if in veg hit them with green cure. Several times within 2 weeks.
If in flower use dr.zymes. Once again, several times, within 2 weeks. This
hasn’t eliminated it from any of my flowering plants, but so far it’s been the
best at keeping it in check. Warning- it will mess with your leaves.
The best solution is to be preventative. Lots and lots of airflow. Do not let plants touch each other. Do not crowd plants.