Pests and diseases - White grubs

If you see miniature mole runs on the surface of the soil in your Bonsai pot it is likely to be a white grub, as seen above.  These are the lava of a beetle which feed off decomposing material in the soil and fine roots.  In the garden, plants are unlikely to be harmed but in the confines of a Bonsai pot root damage, instability and depletion of the nutrients in the soil can occur.

The treatment is to submerge your Bonsai overnight causing the lava to emerge.  Remove the dead or live lava, push the soil down well and dust the surface of the soil with Karbadust or Bexadust and water very lightly.