sulfur burn

So...I knew this day would come, fucking spiders..mitey motherfuckers at that, haven't had them until now and even after countless hours of prior research, when the day comes it's a smack in the face and a kick in the balls, instantaneously it seemed as my eye met the mite I was suddenly brain...

So, I am a first time grower. All was going well until I noticed powdery mildew PM. I used half a cup of sulfur for 22x22 area (2 car garage). The plants are in their first week of flowering. I burned it for two hours. When the smoke had cleared this is what I saw. It broke my heart. Is there...