Practically all the plants I get in have outgrown their pots and are in 3 1/2" solid plastic pots. I just like mesh-pots. Each to their own I guess. I have never used any sort of pesticide/fungicide. I simply haven't seen the need. That's not to say I won't do so in the future. My mixes generally have five components. I think they would be labeled "excellent".
Melissa, have you ever used the slow-release pellets, something like Osmocote? I occasional see someone stating that they use this. I go through 20-30 lbs. of Osmocote each year but have never used it with any orchids.