symptoms for the above fungus are brown rot, root rot and tissue softening rot, resulting in necrosis. thats not whats goin on in OP's plants.
still looks like citrus scale to me. as to fungicide types, the copper methycote products are hard to find in the US now, except in sprays for peach leaf curl fungus and a few other drupe sprays. asking around your local PCAs might pay off, or look for something for peach leaf curl. dont spray while you are flowering as the carrier solution is pretty pungent, and for peaches nectarines and apricots you cant spray after the fruit has set. the silver sprays are new and i dont know if they even work, but they are reputed to be non toxic, and suitable for use all the way up to a few weeks before harvest (on drupes! read the labels of course, and treat cannabis like you would tobacco or soft skinned fruit) but again, if it doesnt work, its wasted money. alternately try reducing your humidity, increasing your under-canopy leaf removal, and adding some ultraviolet light to your spectrum (fungi hate dry conditions, bright light and UV radiation, all of which are largely ignored by most plants)]
Addendum: sulphur smokers are reputed to be great at controlling fungi indoors while being harmless or even beneficial to cannabis. i only treated fungus outdoors on fruit trees so i never used that.
