black on pseudobulb?

[stefpix]

thanks for your opinion
pseudobulb on encyclia is had. i scratched a tiny bit and underneath that dark crust is healthy green.

the Den formosum looks healthy except just in that spot. it is growing new canes and roots and all the other PBs look healthy.
Is spraying with fungicide [spectracide ] enough? or should i cut that cane off? it has probably 7 / 8 canes so maybe better cut off in doubt?
or maybe cut around the black spot and leave the cane?
thanks