Dave Allyn Dave Allyn said:

Help!!! I just went outside to the garden. One of the "branches" of
a yellow bannana pepper was laying on the ground. it looked like it
had been cut off. the middle of the stalk is hollowed out.

what did this and how do I kill it?

It's been and gone, most likely. The prime suspect is the stalk borer.

Here's what the Connecticut Agricultual Experiment Station had to say about
them:
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Stalk borer, Papaipema nebris.
These dirty grayish caterpillars, which are darker with white stripes when young, bore
in the stems of pepper. The eggs of this caterpillar are laid in the fall by the moths on
surrounding grasses and weeds. After hatching in the spring the borers feed on these
plants and later may migrate into adjacent fields where they cause injury. The
caterpillars are very active. Their restless habit of frequently changing from one plant
stem to another increases the damage. Keeping the borders of the vegetable garden
well-mowed and controlling weeds may help deny these insects their breeding
grounds.
---------------------------------------------

And here is a full page, from the University of Vermont Extension Service, on
stalk borers:

http://www.uvm.edu/extension/publications/el/el187.htm

--
Pat in Plymouth MI

Any technology distinguishable from magic is insufficiently advanced.
(attributed to Don Marti)