Yep it is a bug. If you look just down the stem from the wilt you will see some brown lines where it girdled the shoot. They lay an egg inside the stem and the maggot hatches. Just snip off the shoots below the brown lines or gummy spot and dispose of it.

Thank you for the answer. Do you know which kind of bug that is? Tried to google but can't figure it out..

BTW, I bought this bare root Pakistan mulberry tree last early spring. Then the grafted part never leaf out and died. Only the root stock survived and now is 10 feet tall and luckily still gives me around 50 Pakistan mulberry this spring.

I am wondering how come the grafted part died but the root stock grows so vigorously?

Looks like they are all Pakistan mulberry tree.

Root stocks are vigorous.......that is one reason why they are used as root stock:)

Sorry I don't know what bug it is..perhaps it is the same cane borer that attacks raspberry and blackberry canes? Just not sure if that is the same bug. The damage is the same. My mulberries have those folded tips all over it. To me it does not matter because they are fruiting now and when done it will get severely pruned as I want it to be a bush. Here is a pic of the fruit I took the other day.

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