What boring into my stems??? HELP QUICK!!!!

so while visiting my plants today i noticed a little females stem had this huge hole in it how its still standing i dunno, its a runt of a plant so i didnt really sweat it then i noticed a hole in a much larger plants stem... is something inside it eating the stem
are there bugs that do this??
AND most importantly how do i kill the fuckers before it kills one of my best plants of the year??
its an outdoor grow

now someones supposed to tell me whats wrong lol....

Kinda hard to tell without pics man.

EDIT: if it is bugs. Spray some Neems oil. Normally found in vegetable pesticides.