Field Evaluation of Two Formulations of Cyfluthrin for Control of Ixodes dammini and Amblyomma americanum (Acari: Ixodidae) V. B. SOLBERG, K. NEIDHARDT, 1 M. R. SARDELIS, F. J. HOFFMANN, R. STEVENSON,2 L. R. BOOBAR, AND H. J. HARLAN3 U.S. Army Biomedical Research and Development Laboratory, Fort Detrick, Frederick, Maryland 21702-5010
J. Med. Entomol. 29(4): 634-638 (1992) ABSTRACT Liquid or granular cyfluthrin was applied in the spring and fall to different test plots at a rate of 0.41 (AI) kg/ha to control Ixodes dammini Spielman, Clifford, Piesman & Corwin and Amblyomma americanum (L.). Spring application of liquid cyfluthrin showed the most significant decreases of both species. /. dammini nymphs were reduced 97% at 10 d, 100% at 2 mo, and 100% at 1 yr; and A. americanum adults and nymphs were reduced 91-93% at 10 d and 100% at 2 mo posttreatment. Granular cyfluthrin applied in the spring gave 97 and 87% control of nymphal /. dammini 10 d and 2 mo posttreatment, respectively. KEY WORDS Acarina, cyfluthrin, Ixodes dammini, Amblyomma
THERE IS A NEED to develop an
effective,
quick-acting, long-term, cost-effective control method to reduce Ixodes dammini Spielman, Clifford, Piesman & Corwin, the vector of Lyme disease (Burgdorfer et al. 1982). Current control methodologies, such as the use of Damminix (insecticide-treated cotton packaged for retrieval and use by mice for nesting material; EcoHealth, Boston, Mass.) to kill early stages of/, dammini that parasitize mice (Thomas 1988), have drawbacks. Although Damminix was reported to reduce ticks that feed on mice in small areas outside the home, it is not effective against these stages that parasitize other small mammals and birds. In addition, using Damminix to control ticks parasitizing mice in larger areas is costly and time-consuming. A 50% reduction of white-tailed deer, the primary host of adult I. dammini, is ineffective, perhaps because the remaining deer harbor more ticks (Wilson et al. 1984). But when the deer population is virtually eradicated, there is an immediate effect on tick population although it takes at least 3 yr to decrease the adult population (Wilson et al. 1988). Habitat alteration, such as controlled burning of underbrush and other forms of clearing vegetation, are man-hour intensive (Wilson et al. 1988). With regard to controlling all stages of J. dammini with insecticides, the best time for applica1 U.S. Army Environmental Hygiene Agency-North, Field Support Activity, Fort Meade, Md. 20755-5225. 2 Navy Environmental and Preventive Medicine Unit-2, Naval Station, Norfolk, Va. 23511-6288. 3 Uniform Services University of the Health Sciences, Preventive Medicine and Biometrics, Bethesda, Md. 20814-4799.
americanum
tion and duration of control has not been thoroughly investigated. Schulze et al. (1987) reported that late fall was the best time to control adult /. dammini by application of carbaryl and diazinon (liquid formulations) to wooded plots but the effects on overwintering subadults were not determined. Stafford (1991) reported that carbaryl (liquid formulation) applied in June controlled nymphs for almost 2 mo in residential areas but did not control the emergence of larvae in August or adults in the fall. Schulze et al. (1991) recently reported that granular formulations of three acaricides (diazinon, chloropyrifos, and carbaryl) were effective in control of /. dammini nymphs and larvae for 1-2 mo in wooded areas. However, according to Schulze et al. (1991), the reduction of these stages with granular formulations was less impressive than reduction of adults in the earlier study (Schulze et al. 1987) using the liquid formulation. Several studies on /. dammini were previously conducted at Colts Neck, N.J., an endemic area for Lyme disease (Schulze et al. 1984, 1985, 1987, 1991). Amblyomma americanum (L.), a vector of Rocky Mountain spotted fever (Zaki 1989), coexists with 7. dammini in this area and equally infests a variety of mammalian hosts (Schulze et al. 1984). Thus, to compare the efficacy of different formulations and to determine the proper timing of application, a field evaluation of two formulations of cyfluthrin, granular and liquid, was conducted. The field trial compared the efficacy of spring and fall applications
July 1992
SOLBERG ET AL.: APPLICATION OF CYFLUTHRIN FOR TICK CONTROL
for short- and long-term control of all stages of /. dammini and A. americanum in a wooded habitat. Materials and Methods Study Area. The study was conducted in seven sites separated by at least 0.8 km at Naval Weapons Station Earle, Colts Neck, N.J., from May 1989 to May 1990. This oak-dominated forested area, described by Schulze et al. (1987, 1991) is located in an endemic area for Lyme disease. A total of 35 plots (14 by 14 m) was selected, five plots per site. Each plot was separated by untreated zones of >10 m. Five plots in each site were randomly assigned to one of five treatment groups: (1) untreated; (2) cyfluthrin liquid, spring-applied; (3) cyfluthrin granular, springapplied; (4) cyfluthrin liquid, fall-applied; or (5) cyfluthrin granular, fall-applied. Acaricide Application. Two formulations of cyfluthrin (Miles, Inc., Kansas City, Mo.), a pyrethroid, were evaluated. A liquid formulation of cyfluthrin, TEMPO 2 was applied to understory vegetation (
J. Med. Entomol. 29(4): 634-638 (1992) ABSTRACT Liquid or granular cyfluthrin was applied in the spring and fall to different test plots at a rate of 0.41 (AI) kg/ha to control Ixodes dammini Spielman, Clifford, Piesman & Corwin and Amblyomma americanum (L.). Spring application of liquid cyfluthrin showed the most significant decreases of both species. /. dammini nymphs were reduced 97% at 10 d, 100% at 2 mo, and 100% at 1 yr; and A. americanum adults and nymphs were reduced 91-93% at 10 d and 100% at 2 mo posttreatment. Granular cyfluthrin applied in the spring gave 97 and 87% control of nymphal /. dammini 10 d and 2 mo posttreatment, respectively. KEY WORDS Acarina, cyfluthrin, Ixodes dammini, Amblyomma
THERE IS A NEED to develop an
effective,
quick-acting, long-term, cost-effective control method to reduce Ixodes dammini Spielman, Clifford, Piesman & Corwin, the vector of Lyme disease (Burgdorfer et al. 1982). Current control methodologies, such as the use of Damminix (insecticide-treated cotton packaged for retrieval and use by mice for nesting material; EcoHealth, Boston, Mass.) to kill early stages of/, dammini that parasitize mice (Thomas 1988), have drawbacks. Although Damminix was reported to reduce ticks that feed on mice in small areas outside the home, it is not effective against these stages that parasitize other small mammals and birds. In addition, using Damminix to control ticks parasitizing mice in larger areas is costly and time-consuming. A 50% reduction of white-tailed deer, the primary host of adult I. dammini, is ineffective, perhaps because the remaining deer harbor more ticks (Wilson et al. 1984). But when the deer population is virtually eradicated, there is an immediate effect on tick population although it takes at least 3 yr to decrease the adult population (Wilson et al. 1988). Habitat alteration, such as controlled burning of underbrush and other forms of clearing vegetation, are man-hour intensive (Wilson et al. 1988). With regard to controlling all stages of J. dammini with insecticides, the best time for applica1 U.S. Army Environmental Hygiene Agency-North, Field Support Activity, Fort Meade, Md. 20755-5225. 2 Navy Environmental and Preventive Medicine Unit-2, Naval Station, Norfolk, Va. 23511-6288. 3 Uniform Services University of the Health Sciences, Preventive Medicine and Biometrics, Bethesda, Md. 20814-4799.
americanum
tion and duration of control has not been thoroughly investigated. Schulze et al. (1987) reported that late fall was the best time to control adult /. dammini by application of carbaryl and diazinon (liquid formulations) to wooded plots but the effects on overwintering subadults were not determined. Stafford (1991) reported that carbaryl (liquid formulation) applied in June controlled nymphs for almost 2 mo in residential areas but did not control the emergence of larvae in August or adults in the fall. Schulze et al. (1991) recently reported that granular formulations of three acaricides (diazinon, chloropyrifos, and carbaryl) were effective in control of /. dammini nymphs and larvae for 1-2 mo in wooded areas. However, according to Schulze et al. (1991), the reduction of these stages with granular formulations was less impressive than reduction of adults in the earlier study (Schulze et al. 1987) using the liquid formulation. Several studies on /. dammini were previously conducted at Colts Neck, N.J., an endemic area for Lyme disease (Schulze et al. 1984, 1985, 1987, 1991). Amblyomma americanum (L.), a vector of Rocky Mountain spotted fever (Zaki 1989), coexists with 7. dammini in this area and equally infests a variety of mammalian hosts (Schulze et al. 1984). Thus, to compare the efficacy of different formulations and to determine the proper timing of application, a field evaluation of two formulations of cyfluthrin, granular and liquid, was conducted. The field trial compared the efficacy of spring and fall applications
July 1992
SOLBERG ET AL.: APPLICATION OF CYFLUTHRIN FOR TICK CONTROL
for short- and long-term control of all stages of /. dammini and A. americanum in a wooded habitat. Materials and Methods Study Area. The study was conducted in seven sites separated by at least 0.8 km at Naval Weapons Station Earle, Colts Neck, N.J., from May 1989 to May 1990. This oak-dominated forested area, described by Schulze et al. (1987, 1991) is located in an endemic area for Lyme disease. A total of 35 plots (14 by 14 m) was selected, five plots per site. Each plot was separated by untreated zones of >10 m. Five plots in each site were randomly assigned to one of five treatment groups: (1) untreated; (2) cyfluthrin liquid, spring-applied; (3) cyfluthrin granular, springapplied; (4) cyfluthrin liquid, fall-applied; or (5) cyfluthrin granular, fall-applied. Acaricide Application. Two formulations of cyfluthrin (Miles, Inc., Kansas City, Mo.), a pyrethroid, were evaluated. A liquid formulation of cyfluthrin, TEMPO 2 was applied to understory vegetation (
