something eating up my catasetum root !!!!

[catasetum-ian]

something is eating up my catasetum's root, leaving round small circular defect on the root. something like a tub ice cream being scoop off a hole.
caught a three black color small snails before, had been applying mollusicide and pesticide...problem stop for about a week or two and now it is coming back. need help to get rid of these pests.
wanted to do repotting but the catasetum is halfway maturing the new bulb, re potting now would caused an underdeveloped bulb size. to make thing worst, that pot is my biggest pileatum of all
any remedy that i can try to get rid of whatever that is causing the problem. thanks