In the Adirondacks, the ban on aerial applications of pesticides took affect in the 1980's. Since that time, Bti, (Bacillus thuringiensis israelensis), is the only pesticide the NYSDEC allows for the control of biting insects on State Forest Preserve lands. It is extremely specific in targeting black fly larvae, and non-persistent in the environment.
Despite the ongoing efforts to stem the annual invasion of 'flying teeth', blackflies continue to inflict pain, especially on small children, and adults with above average sensitivity to the bites.
I've witnessed unsuspecting victims with eyes swollen shut from black fly bites, and I've seen children sickened by prolonged exposure to these insects. Victims often have the appearance of a giant cranberry muffin, albeit with legs and arms.
In an effort to guard against such injuries, a wide variety of repellants have been developed. The most effective often have high concentrations of DEET, (N,N-diethyltoluamide).
Unfortunately, concerns remain about the safety of using this chemical on humans. DEET may cause allergic reactions in children, and the higher the concentration, the greater the risk. However, studies reveal concentrations of just 30 percent DEET can be just as effective and much safer, than 100 percent concentrations.
There are numerous natural, insect repellents on the market, which contain ingredients such as citronella oil, pennyroyal, camphor, eucalyptus,lemon juice and spearmint. Even Avon's Skin-So-Soft seems to work, but only if it is very liberally applied.
Over the years, I've used a variety of natural products including Green Ban, Z'off, Naturapel, Bug-B-Gone and BuzzAway. Some work, most don't.
However, the most effective I've found is "Ole Time" Woodsman Fly Dope, which is also DEET free. Ole Time Woodsman has the added benefit of keeping people and small dogs at bay. Conveniently, the not-so-fragrant scent will also assure you a private seat at local restaurants, one that is far removed from the crowd.