INFLUENCE OF SNAKEWEED FOLIAGE ON ENGORGEMENT, FECUNDITY AND ATTACHMENT OF THE LONE STAR TICK (ACARI, IXODIDAE)

Nymphal lone star ticks, Amblyomma americanum, were allowed to engorge on domestic rabbits that had received diets containing 0, 5 or 10% pe rennial snakeweed foliage. Tick attachment was reduced 39 and 35% on r abbits ingesting 5 and 10% snakeweed foliage, respectively. Adult tick s reared from engorged nymphs showed no treatment differences in survi vability, engorgement weight or hatchability of egg masses. In a study conducted on sheep, adult ticks, confined in cells to an area with ha lf of the skin surface treated with methylene chloride extracts of sna keweed foliage, attached significantly less often to treated skin comp ared to cells half-treated with acetone. When confined in cells to an area totally treated with snakeweed foliage extracts, a mean of 12.5, 4.5 and 0 ticks (out of 40 ticks per cell) attached to skin treated wi th acidic, basic or neutral extracts, respectively, compared to a mean of 16.7 in acetone-treated cells.