title: Suppression of host-seeking Ixodes scapularis and Amblyomma americanum (Acari: Ixodidae) nymphs after dual applications of plant-derived acaricides in New Jersey.
abstract: We evaluated the ability of dual applications of natural, plant-derived acaricides to suppress nymphal Ixodes scapularis Say and Amblyomma americanum (L.) (Acari: Ixodidae) in a Lyme disease endemic area of New Jersey. An aqueous formulation of 2% nootkatone provided >90% control of I. scapularis through 7 d. Control declined to 80.9% at 14 d, and a second application was made that provided >95% control through the remaining 4 wk of the nymphal season. Nootkatone provided >90% control of A. americanum through 35 d postapplication. Applications of 2% carvacrol and EcoTrol T&O resulted in rapid knockdown of both tick species, but control declined significantly to 76.7 and 73.7%, respectively, after 14 d when a second application was made that extended control of both tick species to between 86.2 and 94.8% at 21 d. Subsequently, control declined steadily in all plots by 42 d postapplication except for I. scapularis in carvacrol-treated plots, where levels of control >90% were observed through 35 d. Of the three compounds tested, 2% nootkatone provided the most consistent results, with 96.5 and 91.9% control of I. scapularis and A. americanum through 42 and 35 d, respectively. The ability of plant-derived natural products to quickly suppress and maintain significant control of populations of these medically important ticks may represent a future alternative to the use of conventional synthetic acaricides. In addition, the demonstrated efficacy of properly-timed backpack sprayer application may enable homeowner access to these minimal-risk acaricides.
authors.affiliation: Freehold Area Health Department, 1 Municipal Plaza, Freehold, NJ 07728, USA. rajordanphd@optimum.net
authors.forename: Robert A
authors.initials: RA
authors.lastname: Jordan
authors.forename: Marc C
authors.initials: MC
authors.lastname: Dolan
authors.forename: Joseph
authors.initials: J
authors.lastname: Piesman
authors.forename: Terry L
authors.initials: TL
authors.lastname: Schulze
mesh_terms: D056810:Acaricides / Q000008:administration & dosage*; D000818:Animals; D000081007:Cymenes; D018884:Ixodes; D039821:Monoterpenes / Q000008:administration & dosage*; D009515:New Jersey; D009758:Nymph; D010936:Plant Extracts / Q000008:administration & dosage; D000081223:Polycyclic Sesquiterpenes; D012717:Sesquiterpenes / Q000008:administration & dosage*; D013983:Tick Control
chemical_list: D056810:Acaricides; D000081007:Cymenes; D039821:Monoterpenes; D010936:Plant Extracts; D000081223:Polycyclic Sesquiterpenes; D012717:Sesquiterpenes; C073316:carvacrol; C050302:nootkatone