Downy mildews of crops are caused by

Powdery mildews of crops are caused by

Powdery mildew of crops is caused by

Powdery mildew of crops is caused by

Powdery mildew of crops is caused by

Powdery mildew of crops is caused by

The smuts of crop plants are caused by

The smuts of crop plants are caused by

The smuts of crop plants are caused by

The smuts of crop plants are caused by

In a region of France, Downy mildew of grapes was confined to large varieties of grapes. Which of the following measures could be taken to grow grape vines in that region? a. Use of disease resistant varieties. b. Spray with Bordeaux mixture. C.Use of a chemical fertiliser. d. Spray with an insecticide.