Quick and easy article to get a 1 Gallon neem oil spray.
Works well for various pests, including aphids, ants and fungus. Beware this will also deter the beneficial insects, which might not be idle in all cases. So use this only when the pests are in large numbers that aren’t controllable in other means.
For powdery white mildew add a tsp of baking soda to this mix.
1 tsp – Soap
4 tsp – Neem oil
Mix it with warm water to get the oil mixed in water really well
Now dilute the mixture with about 1 Gallon of cold water and spray it away
Follow-up: This needs to be repeated in a few days after monitoring the pest activity to completely stop them.