SILT FENCING AS A BARRIER TO THE DISPERSAL OF IXODES-SCAPULARIS (ACARI, IXODIDAE) INTO PASTURES

Silt fence barriers were set along pasture fencelines and evaluated as a method of restricting the dispersal of blacklegged tick, Ixodes sca pularis Say, adults and nymphs from woodlands into adjacent horse past ures. The barriers received no acaricidal treatment for the Ist cohort of adults. Thereafter the woods side of the barriers was sprayed with cyfluthrin at the onset of each season of host seeking activity of ny mphs and adults. When high densities of adults were present, the barri ers significantly limited the numbers of ticks in pastures. Nymphs, ho wever, were not significantly fewer in numbers in pasture areas associ ated with the barriers compared with control areas. Marked adult ticks released in woodlands and ecotones were recaptured on mowed verges an d pastures, but there was little dispersal from the woods edge into th e woods.