Death.

Death is like the insect
Menacing the tree,
Competent to kill it,
But decoyed may be.

Bait it with the balsam,
Seek it with the knife,
Baffle, if it cost you
Everything in life.

Then, if it have burrowed
Out of reach of skill,
Ring the tree and leave it, --
'T is the vermin's will.