Hole in stem

Hi, is a job done by bastard worm, it had appens to me lots of years ago. I'd killed the bastard introducing a very thin metal wire (braided electric davo) to prick and kill the worm deeply after spraying the hole with a solution of water and soluble sulfur. Generally these worms belong to the "cossus cossus" family, they are white or ivory with black or red head and are very harmful. 👊