help-hylocereus [dragon fruit]

hi all. i need advice on my dragon fruit plants...i have quite a few plants i grew from cuttings, for grafting attemps, how ever we had about 5 days of heavy rain, thus the plants have lots of, i call rust spots, orang,i.e. brown, looks like the rain stayed on them, what can i do to right this concern, will it spread if it is rust, i have sulfa powder but i,ll to hopefully hear back from members, the main i,em concerned about is a yellow fruit one with 4 ribs, i hear there the best for grafting, if you can advice me that will be great reguards peter olsen vic [ p.s. there over 4 foot high.]