There is nothing in Coco its Inert! Coconut Husk/Pith is not a food Source. Its is possible to have bark beetles/or beetles but they rarely stick around and are of no concern...Its why many of Us use Coco/Hydro, it is less attractive to Pests... Many on the forums will video the "Offending Scarabs" for Identification.... If over wetted it can attract fungus gnats which is a Vector for other Pathogens. If Your adding some black gunky nutrients/molasses your plants dont need, the sugars will attract several types of insects/pests... What Inputs are you using in your Coco?