It has mainly activities protective and curative but also eradicated by contact and during the vapor phase. This phase is very effective against colonies of ectoparasitic no well established. For this reason, its effectivity depends on the temperature.

Juan

May be sulfur changes the pH of the leaves that are highly effective for further growth of powdery mildew.

The sulfur produce H2S as a vapor face, and it is toxic for fungi, also the sulfur use for protecting the plant from getting an infection with powdery mildew but it is not useful for cure the plant if the infection is already happening.