Sounds like the stalk borer at work. Nasty little pest. Sometimes if you slit open the stalk on a branch that's wilting, you can catch them at it.

I'm not particularly familiar with control strategies, but hopefully an ID will help you search for them. I do know it has a very broad host range, and isn't normally (ha) a big problem.

Hope that helps.

--Alison
who has endured year after year of earwig depredations, and they aren't "normally" a significant pest either.