
-oy! --the pic tells the tale, mate that's some form of powdery mildew hitting the stems and leaves! It can happen even if your tent
ambient T and RH are okay.. it the proximity to the constant, high moisture/RH spots that can still promote it,... problem is, the spores are for all practical purposes, present all the times, everywhere, like dust...just looking for that perfect spot! ---So, no way around it: time to cut the infected parts off, and treat the rest; dip your scissors into alcohol, then gently slip the infected parts into a baggie, then cut the stem near the base...dip, cut, dip, cut until all the visually suspect parts are removed,... Treat with pure neem oil (coco surface too), or some other food safe fungicide,... there are some products like Serenade, which are biological control agents (bacteria), which are very effective....Serenade stinks like hell for a couple days though! And yes, a gentle cross breeze will help make proximity conditions less favorable,...

Cheers Carl, thanks for the rep' too!
