Hello again guys. I have included what should be a better/clearer photo of the problem I have been having. It has been suggested to me that it might be worms but I have submerged the tree under water for over an hour and nothing surfaced. I have checked the foliage and for any identifiable pests without success. I have locked the tree away in a room overnight in the event that the cause might be a foreign body but when I opened the door in the morning the same things happened. What I want to know is that if it is in fact a grub residing in the soil, how can I get rid of it??

Thanks

I have to agree with Brenden is not from the potting mix. To me is some digestive discard. Pretty sure is some form of droping. Other than that I am with you
Cheers
Leong