I actually wondered about this before, for roleplay/fic purposes I invented a modification that fits onto a Dracon beam and eliminates Kandrona from anything it's aimed at. Because I'm just that nerdy
I was thinking more along the lines of obliterating the stored energy that Yeerks might be producing in their cells--like plants producing glucose from chloroplasts--and causing starvation (or reversing it) with an energy beam. How else can the Yeerks make Kandrona starvation last so long? I remember somewhere in Visser it was mentioned that the Council of Thirteen lives within some kind of refined stream of Kandrona that allows them to feed without leaving their hosts as often. That means it'd be passing through their host's skulls o.O; And we all think cell phones are gonna screw with people's brains...!