I have given orchid talks in Houston, in August twice. Yes, I went back a second time. The last time I left Houston just 7 days before Harvey hit. The HOT HUMID weather was unbearable. That said, I would explore some cultural tricks to be less favorable for fungus in July.
Not seeing more of your place than a few photos I can not pretend to know what you need. I'll tick off some ideas, and if they make sense try them out. If not, try something else.
To cure fungus, more often than not, modifying the environment is more effective than chemical treatment.
Air movement - shift plants off the ground at least a foot or two. Expanded metal mesh shelves are preferable to solid wood shelves as air can flow from all directions. Do not crowd plants together on the shelves, allow air spaces. This will also slow spread of crawling insects.
If air is frequently still, calm with no wind. Consider adding a fan. Leaves should have enough air moving at all times that you can see movement. Where I live adding a fan outdoors would be foolish, but I don't know your microclimate.
Shade cloth should be up before 95F heat hits, 40% to 60% is what I have used for "full sun" orchids. Purpose is to keep leaf temps down below 110 F. Air movement and shade will help both counts.
Others might have ideas to consider.
Hope this helps.