We have bought and used clothing that's impregnated with a product called Permathrin (sp?) when we did a week long kayak trip down the Allagash River in Maine.
The area is known for black flies and my wife was really worried about it but the clothing works! We later found out that U.S. military uniforms have been treated with this. We also found that you can buy it as a spray and pretreat your own clothing at home before you leave on your trip.
Good luck!
PS. Lookie here!
http://www.cabelas.c...&Ntt=Permathrin
Edited by smlobx, 11 August 2015 - 09:43 PM.