Layne,
 I’m quite sure of the soap acting as a surfactant, this was explained to me
when I was a bee inspector, and I was told this is how fire departments kill
Africanized bees.
 As for whether soap residue killed bees I would need more information.
There is no certainty the soap was the factor.  How about pesticide, mites,
etc.  Perhaps the beekeeper can inform us as to the details, I can't find
that letter.
 As for insecticidal soaps, I don’t think there are insecticides involved
there, more repellents and the suffocant effect.
 By the way, I was in your town on a night out while working at Weaver
Apiaries in 1977.  Is the Dixie Chicken still in biz?  I had lots of fun in
that place!  What kind of honey do you get in your area?
Charles F. Andros
Former NH/VT Apiary Inspector '78-’89
Linden Apiaries/Boulder Wall Gardens
1 McLean Road
POB 165
Walpole, NH 03608-0165 USA/EUA
603-756-9056 phone/fax if notified by phone
email: [log in to unmask]
Latitude: 43° 05’ North
Longitude: 72° 21’ 15” West
Keeper of 41 2-queen colonies for honey, pollen, propolis, pollination,
apitherapy, nuclei, and beeswax