Darkstar, there are MANY species of PM fungi, I've already dealt with a species that had no problem propagating itself in 30% RH. Lowering RH is not automagically a cure for PM, people need to let go of that idea.
I use something called excell LG. I think it is organic. I know it is systemic. But i also use the sulfer burner. Just stop it before flowers start.
I just picked this stuff up, will be experimenting with it on an as-needed basis.
Someone recommended this. Peace GS
I ordered Oxidate today. Only comes in 2 1/2 gallon bottles, 191.00 with shipping. The lady from the company said it can be used up till harvest for medical marijuana. It kills many diseases, can be used every few days, and nothing can supposedly build a tolerance to it. As with the agri fos, I will report my results.
Non-systemic, foliar only, and let it come with a word of warning to you--be VERY careful! You'll have to really saturate the girls, and there is a real risk of burning the living shit out of them if treatment requires using the 2oz/gal dosing rates. Burning to the point of making buds shrink.
I know because I did it last week, fortunately only one girl burned like that. I'm going with a systemic ASAP, I'm sick of all this God damn foliaring.
Another word of caution, let it be a very strong caution for you--USE THE PPG! Especially a respirator. Do not fuck around with this stuff. Ventilate very, very well when using it, DO NOT let it splash, especially the straight OxiDate, do not allow contact with bare skin or clothing. Remove any clothing that's made contact immediately and wash that clothing.