Is it outside, I think it will be fine if you act now, if it is outside it maybe slugs, if so get slug repellent it worked perfect for me, but if you have a dog do not let it near it, it is deadly to dogs and thet like it for some reason.
If its outside have a real close look at it rite around dusk or shortly after, there may be slugs crawling there way up your stalk, check under the leaves, but i think they only come out at night.
Like i said keep pets away from slug repelent.
Also you can put a plate of beer beside it the slugs love beer they crawl in and drown.
Someone here will help you if it isnt slugs.