deerfern ...... I have a supposed product-equivalent ....
Click Here.
Just make sure the concentration mix is correct. And you spray onto the leaves, which then gets absorbed into the plant, and works down into the roots.
If your bulb and leaves aren't rotting, then there's probably no need to apply it. Just have this 'handy' and waiting - ready to use if leaves and/or bulb is rotting.
Usually, if the watering method is satisfactory, and the roots don't always stay soggy and dripping wet, and the leaves and bulb get adequate air-flow, then rotting becomes rare ------ or completely avoided.
I encountered minor rotting of bases of catasetum leaves last year - and the yates anti-rot phosacid stopped that particular kind of rot in its tracks. A suitable treatment can work wonders.