Best thing to do for plant disease?

Question

There is a white powder all over the leaves of my pumpkin plant. The leaves are turning yellow/brown and drying up. What can I do?

Answer 1

Its powdery mildew, a fungicide will take care of it.  Also try not to water at night as this is the time when fungus grows.  Water in the morning giving the leaves a  chance to dry off.  You can't do anything about the rain but you can control the time of day that you water.

Answer 2

Sounds like powdery mildew.  Apply a fungicide.