Not saying this is the best answer, but I would take the plant out of the soil and rinse throughly and then set it in a clear container with only water until im sure the pests will not return before re-potting in soil.

Goodluck

Yes take it out of the soil and give it a bath. Fill a bucket with warm tap water add a few drops of dawn dish soap and stir it up, but not enough to make bubbles. Dip the plant in the solution and make sure you clear the roots of debris by gently running your fingers through them. Then take it out of the soapy water, rinse the roots off with tap water but don't rinse the rest of the plant. Finally plant the bamboo in a vase with just the roots under bottled or distilled water with about an inch of water covering the roots. Let sit and monitor for bugs. I'm not sure what type of bugs you have, but this method gets rid of spider mites.... Hope this helps.