Have you built your own device for that?
I have first done tests with dc current with higher voltages and without a frequency and the worms seems to be disturbed even in the head, in the lungs, in the digestive tube :)
It produces die off but i think that to add a frequency will improve the killing effect.
My approach is to do selective electrocution with a high enough current. The frequency of the human body is not 50hz or 60Hz (according to the reports by Hulda Clark and Georges Lakhovsky) but you can kill it with a high enough current and this frequency. It probably damages the materials of the body or the "life beat".
So by using a high enough current (but low enough to not damage the human body too much) and a frequency, i guess electrons will damage the materials or the "life beat" of the worms.
What is interesting is that by using electrodes in a specific way with water, i can take up to 20mA without too much pain when the Ultimate zapper is at 1mA to 3mA max.
This is really promising :).
Does it operate on a single frequency?
I will report this later if i manage to produce more die off.