ACTIVITY OF REPELLANTS APPLIED TO SKIN FOR PROTECTION AGAINST AMBLYOMMA-AMERICANUM AND IXODES-SCAPULARIS TICKS (ACARI, IXODIDAE)

Twenty-nine repellents were tested on human skin for duration of activ ity as protectants against nymphal lone star ticks (Amblyomma american um) and against black-legged or deer ticks (Ixodes scapularis Say). El even of these repellents, including deet, provided >2 h of protection against the lone star tick. One repellent, 1-(3-cyclohexenyl-ylcarbony l) piperidine, was effective greater than or equal to 4 h. Four repell ents (2 pyridines and 2 piperidines with protection lasting 2.3-3 h) s howed acaricidal activity to more than half of the ticks tested after 9-12 min of exposure. Seven repellents that were most effective agains t A. americanum, including deet, were tested against the black-legged tick. None was effective and no knockdown was observed. These results suggest that the black-legged tick is less sensitive to repellents tha n the lone star tick.