Yellowing leaves with brown patches?

Just last week everything was looking great with my Dinafem Cheese. How quickly things change.

This week I noticed a few brown patches on the lower leaves. I thought it was probably a little leaf burn from a foliar spray I did for a mild case of powdery mildew.

Other than that, she looked fine this morning when I watered. However I just got home from work and checked on her to find major yellowing in the lower leaves. Can anyone offer me advice? I'd really love to save her if I can.

(It's been very hot today. Temps are around 104 with a heat index of 115+. Next week we'll be back in the 90s. Could it be heat stress related? My other plants look okay. )

Here are some pics. i'm not sure why they didn't attach earlier

What kind of spray did u use? When did u spray?

I've been alternating spraying with Spectracide Immunox and Gardensafe Fungicide 3 every 3-4 days for the past month or so. The browning happened the day after I applied the Gardensafe. I sprayed with the Immunox this morning. After work today is when I noticed the yellowing.
I've got a mild case of powdery mildew. While not cured, it has been very slow to spread over the past month. I thought the sprays were helping.

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