How to solve the problem powdery mildew of watermelon

Usually this disease affects the leaves and attacks its lower and upper part.
The spots appear as a yellow to white powder on the lower and upper surface of the leaves.
For managing them,use Azoxystrobin 11% + Tebuconazole 18.3% SC @ 300 ml/acre or Azoxystrobin 23 % SC @ 300 ml/acre.
Spray Trichoderma viride @ 500 g/acre + Pseudomonas fluorescens @ 250 gram/acre as a biological treatment.