VETERINARY ENTOMOLOGY
Efficacy of Cyhalothrin and Lambdacyhalothrin Against Boophilus microplus (Acari: Ixodidae) R. B. DAVEY,1 E. H. AHRENS,1 AND J. E. GEORGE 2
J. Econ. Entomol. 85(6): 2286-2290 (1992)
KEY WORDS cyhalothrin, lambdacyhalothrin, Boophilus microplus
SINCE THE INCEPTION of a federally funded eradication program in 1906, the elimination of Boophilus spp. ticks from the United States has been accomplished primarily through the systematic treatment of livestock with various acaricidal compounds. In the beginning of this program, crude oil was the only means of treatment, but by 1915 the program had switched almost entirely to arsenical dip as the preferred method of treatment. Arsenic continued to be used until the mid-1960s when the organophosphorous compounds became popular. Since 1968, these materials have been used almost exclusively in the fever tick eradication program (Graham & Hourrigan 1977). In recent years, the increased public awareness over injudicious and excessive use of hazardous materials has led the U.S. Environmental Protection Agency (EPA) to reevaluate, reregister, and eliminate many of the pesticides available for a multitude of agricultural uses, including the tick eradication program. Since 1988, two organophosphorous acaricides (dioxathion and crotoxyphos), which have been used extensively in the U.S. tick eradication program, have been removed from the public market. At present, the organophosphorosus acaricide coumaphos is This article reports the results of research only. Mention of a commercial or proprietary product does not constitute an endorsement or a recommendation for its use by USDA. 1 Cattle Fever Tick Research Laboratory, USDA-ARS, P.O. Box 969, Mission, TX 78572. 2 Knipling-Bushland U.S. Livestock Insects Research Laboratory, USDA-ARS, 2700 Fredericksburg Road, Kerrville, TX 78028.
used almost exclusively in the eradication program against Boophilus ticks. However, coumaphos is also under examination by the EPA, and its future availability is in doubt. In addition to the potential elimination of some of the currently used acaricides from the marketplace, the widespread development of acaricide resistance in fever tick populations remains a grave concern. Coumaphos resistance in populations of B. microplus (Canestrini) has been reported by Mexican tick program officials at several locations in Mexico. This resistance has been confirmed by Bull & Ahrens (1988) and Harris et al. (1988). Because of these concerns, the evaluation of alternate nonorganophosphorus acaricides that are not persistant and are rapidly biodegradable in the environment, and which show little tendency for bioaccumulation in organisms, is of utmost importance to the continued success of the U.S. cattle fever tick eradication program. One group of alternative pesticides, the pyrethroids, has provided varying degrees of efficacy against Boophilus ticks. Even though the use of pyrethroids has produced acaricide resistance in B. microplus populations in Australia (Nolan et al. 1989), no such resistance has been reported in Mexico or the United States in Boophilus spp. Davey & Ahrens (1984) reported adequate control of B. microplus and B. annulatus (Say) with permethrin and fenvalerate. Stubbs et al. (1982) achieved a high level of control of major resistant strains of B. microplus with cyhalothrin (a pyrethroid) in field trials. The general advantages of using pyrethroids are that they are rapidly deg-
Downloaded from http://jee.oxfordjournals.org/ by guest on April 12, 2016
ABSTRACT A study was conducted to determine the efficacy of cyhalothrin and lambdacyhalothrin as a whole-body spray and lambdacyhalothrin as a pour-on application on cattle infested with Boophilus microplus (Canestrini). A laboratory bioassay was also done with both spray formulations. Cattle were infested with all parasitic life stages of B. microplus, then treated with 0.007 or 0.01% (AI) concentrations of cyhalothrin as a spray; 0.005, 0.007, or 0.01% (AI) concentrations of lambdacyhalothrin as a spray, or 1% (AI) lambdacyhalothrin as a pour-on. As determined by calculations of the index of reproduction (IR), the 0.007 and 0.01% (AI) cyhalothrin provided 92.4 and 97.3% control, respectively; the 0.005, 0.007, and 0.01% (AI) lambdacyhalothrin provided 92.4, 98.2 (average of two treatments) and 99.3% control, respectively; and the lambdacyhalothrin pour-on treatment provided 0.26), indicating that they are parallel and that the two compounds respond similarly with increasing concentrations of Al. However, the intercepts of the regression lines were significantly different (F = 10.3; df = 1,96; P < 0.01), indicating that lambdacyhalothrin is more effective against B. microplus than cyhalothrin. The IC 50 and IC 99 values indicated that the magnitude of the difference between the two formulations ~2fold, with the lambdacyhalothrin being the more effective of the two.
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JOURNAL OF ECONOMIC ENTOMOLOGY
Acknowledgments The authors thank H. D. Peterson (USDA-ARS) for analyzing the data. We also thank W. J. Gladney (Cooper's Animal Health, Kansas City, KS) for technical assistance and providing the material for evaluation. References Cited Abbott, W. S. 1925. A method for computing the effectiveness of an insecticide. J. Econ. Entomol. 18: 265-267. Ahrens, E. H., R. B. Davey & J. E. George. 1988. Flumethrin applied as a pour-on and whole-body spray for controlling cattle tick (Acari: Ixodidae) on cattle. J. Econ. Entomol. 81: 1133-1136. Bull, D. L. & E. H. Ahrens. 1988. Metabolism of coumaphos in susceptible and resistant strains of
Boophilus microplus (Acari: Ixodidae). J. Med. Entomol. 25: 94-98. Davey, R. B. & E. H. Ahrens. 1982. Control of Boophilus ticks on cattle with a flowable formulation of coumaphos. J. Econ. Entomol. 75: 228-231. Davey, R. B. & E. H. Ahrens. 1984. Control of Boophilus ticks on heifers with two pyrethroids applied as sprays. Am. J. Vet. Res. 45: 1008-1010. Drummond, R. O., S. E. Ernst, J. L. Trevino, W. J. Gladney & O. H. Graham. 1973. Boophilus annulatus and Boophilus microplus: laboratory tests of insecticides. J. Econ. Entomol. 66: 130-133. Drummond, R. O., O. H. Graham, S. E. Ernst & J. L. Trevino. 1967. Evaluation of insecticides for the control of Boophilus annulatus (Say) and Boophilus microplus (Canestrini) (Acarina: Ixodidae) on cattle. Int. Congr. Acarol. 2: 493-498. Graham, O. H. & J. L. Hourrigan. 1977. Eradication programs for the arthropod parasites of livestock. J. Med. Entomol. 13: 629-658. Harris, R. L., J. E. George, E. H. Ahrens, R. B. Davey & H. O. Bazan. 1988. Selection for resistance to coumaphos in a strain of southern cattle tick (Acari: Ixodidae). J. Econ. Entomol. 81: 545-548. Nolan, J., J. T. Wilson, P. E. Green & P. E. Bird. 1989. Synthetic pyrethroid resistance in field samples in the cattle tick (Boophilus microplus). Aust. Vet. J. 66: 179-182. SAS Institute. 1985. SAS/STAT guide for personal computers, version 6 ed. SAS Institute, Cary, NC. Steel, R.G.D. & J. H. Torrie. 1960. Principals and procedures of statistics. McGraw-Hill, New York. Stendel, W. 1985. Experimental studies on the tickicidal effect of Bayticol pour-on. Vet. Med. Rev. 2: 99-111. 1986. Studies on the distribution of flumethrin pour-on on the skin surface and the haircoat of cattle. Vet. Med. Rev. 1: 28-33. Stubbs, V. K., C. Wilshire & L. G. Webber. 1982. Cyhalothrin—A novel acaricidal and insecticidal synthetic pyrethroid for the control of the cattle tick (Boophilus microplus) and the buffalo fly (Haematobia irritans exigua). Aust. Vet. J. 59: 152-155. World Health Organization (WHO). 1990. Environmental health criteria 99: cyhalothrin. Geneva. Received for publication 3 March 1992; accepted 6 July 1992.
Downloaded from http://jee.oxfordjournals.org/ by guest on April 12, 2016
ing that coumaphos is 100% effective against the immature stages of B. microplus ticks. This distinction is important. Maximum efficacy of an acaricide is critical in an eradication program because, under present conditions, cattle infested with B. microplus can be moved into or within the United States 7 d after treatment with coumaphos. The results of our study suggest that cyhalothrin and lambdacyhalothrin would be efficacious in a control program where reduction in tick burden is the objective. However, these acaricides would be unsatisfactory in an eradication program where total elimination of parasitic ticks is the goal. Overall control with the 0.01% (AI) concentration of lambdacyhalothrin may reach >99%, but this is not the only criterion for efficacy of an acaricide. Other factors determine effectiveness of a compound, including the quantity of eggs produced by treated females, the hatch of eggs from treated females, and the length of time female ticks continue to feed on cattle after treatment. In terms of these latter factors, cyhalothrin and lambdacyhalothrin may not be good candidates for an eradication program.
Vol. 85, no. 6
Efficacy of Cyhalothrin and Lambdacyhalothrin Against Boophilus microplus (Acari: Ixodidae) R. B. DAVEY,1 E. H. AHRENS,1 AND J. E. GEORGE 2
J. Econ. Entomol. 85(6): 2286-2290 (1992)
KEY WORDS cyhalothrin, lambdacyhalothrin, Boophilus microplus
SINCE THE INCEPTION of a federally funded eradication program in 1906, the elimination of Boophilus spp. ticks from the United States has been accomplished primarily through the systematic treatment of livestock with various acaricidal compounds. In the beginning of this program, crude oil was the only means of treatment, but by 1915 the program had switched almost entirely to arsenical dip as the preferred method of treatment. Arsenic continued to be used until the mid-1960s when the organophosphorous compounds became popular. Since 1968, these materials have been used almost exclusively in the fever tick eradication program (Graham & Hourrigan 1977). In recent years, the increased public awareness over injudicious and excessive use of hazardous materials has led the U.S. Environmental Protection Agency (EPA) to reevaluate, reregister, and eliminate many of the pesticides available for a multitude of agricultural uses, including the tick eradication program. Since 1988, two organophosphorous acaricides (dioxathion and crotoxyphos), which have been used extensively in the U.S. tick eradication program, have been removed from the public market. At present, the organophosphorosus acaricide coumaphos is This article reports the results of research only. Mention of a commercial or proprietary product does not constitute an endorsement or a recommendation for its use by USDA. 1 Cattle Fever Tick Research Laboratory, USDA-ARS, P.O. Box 969, Mission, TX 78572. 2 Knipling-Bushland U.S. Livestock Insects Research Laboratory, USDA-ARS, 2700 Fredericksburg Road, Kerrville, TX 78028.
used almost exclusively in the eradication program against Boophilus ticks. However, coumaphos is also under examination by the EPA, and its future availability is in doubt. In addition to the potential elimination of some of the currently used acaricides from the marketplace, the widespread development of acaricide resistance in fever tick populations remains a grave concern. Coumaphos resistance in populations of B. microplus (Canestrini) has been reported by Mexican tick program officials at several locations in Mexico. This resistance has been confirmed by Bull & Ahrens (1988) and Harris et al. (1988). Because of these concerns, the evaluation of alternate nonorganophosphorus acaricides that are not persistant and are rapidly biodegradable in the environment, and which show little tendency for bioaccumulation in organisms, is of utmost importance to the continued success of the U.S. cattle fever tick eradication program. One group of alternative pesticides, the pyrethroids, has provided varying degrees of efficacy against Boophilus ticks. Even though the use of pyrethroids has produced acaricide resistance in B. microplus populations in Australia (Nolan et al. 1989), no such resistance has been reported in Mexico or the United States in Boophilus spp. Davey & Ahrens (1984) reported adequate control of B. microplus and B. annulatus (Say) with permethrin and fenvalerate. Stubbs et al. (1982) achieved a high level of control of major resistant strains of B. microplus with cyhalothrin (a pyrethroid) in field trials. The general advantages of using pyrethroids are that they are rapidly deg-
Downloaded from http://jee.oxfordjournals.org/ by guest on April 12, 2016
ABSTRACT A study was conducted to determine the efficacy of cyhalothrin and lambdacyhalothrin as a whole-body spray and lambdacyhalothrin as a pour-on application on cattle infested with Boophilus microplus (Canestrini). A laboratory bioassay was also done with both spray formulations. Cattle were infested with all parasitic life stages of B. microplus, then treated with 0.007 or 0.01% (AI) concentrations of cyhalothrin as a spray; 0.005, 0.007, or 0.01% (AI) concentrations of lambdacyhalothrin as a spray, or 1% (AI) lambdacyhalothrin as a pour-on. As determined by calculations of the index of reproduction (IR), the 0.007 and 0.01% (AI) cyhalothrin provided 92.4 and 97.3% control, respectively; the 0.005, 0.007, and 0.01% (AI) lambdacyhalothrin provided 92.4, 98.2 (average of two treatments) and 99.3% control, respectively; and the lambdacyhalothrin pour-on treatment provided 0.26), indicating that they are parallel and that the two compounds respond similarly with increasing concentrations of Al. However, the intercepts of the regression lines were significantly different (F = 10.3; df = 1,96; P < 0.01), indicating that lambdacyhalothrin is more effective against B. microplus than cyhalothrin. The IC 50 and IC 99 values indicated that the magnitude of the difference between the two formulations ~2fold, with the lambdacyhalothrin being the more effective of the two.
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JOURNAL OF ECONOMIC ENTOMOLOGY
Acknowledgments The authors thank H. D. Peterson (USDA-ARS) for analyzing the data. We also thank W. J. Gladney (Cooper's Animal Health, Kansas City, KS) for technical assistance and providing the material for evaluation. References Cited Abbott, W. S. 1925. A method for computing the effectiveness of an insecticide. J. Econ. Entomol. 18: 265-267. Ahrens, E. H., R. B. Davey & J. E. George. 1988. Flumethrin applied as a pour-on and whole-body spray for controlling cattle tick (Acari: Ixodidae) on cattle. J. Econ. Entomol. 81: 1133-1136. Bull, D. L. & E. H. Ahrens. 1988. Metabolism of coumaphos in susceptible and resistant strains of
Boophilus microplus (Acari: Ixodidae). J. Med. Entomol. 25: 94-98. Davey, R. B. & E. H. Ahrens. 1982. Control of Boophilus ticks on cattle with a flowable formulation of coumaphos. J. Econ. Entomol. 75: 228-231. Davey, R. B. & E. H. Ahrens. 1984. Control of Boophilus ticks on heifers with two pyrethroids applied as sprays. Am. J. Vet. Res. 45: 1008-1010. Drummond, R. O., S. E. Ernst, J. L. Trevino, W. J. Gladney & O. H. Graham. 1973. Boophilus annulatus and Boophilus microplus: laboratory tests of insecticides. J. Econ. Entomol. 66: 130-133. Drummond, R. O., O. H. Graham, S. E. Ernst & J. L. Trevino. 1967. Evaluation of insecticides for the control of Boophilus annulatus (Say) and Boophilus microplus (Canestrini) (Acarina: Ixodidae) on cattle. Int. Congr. Acarol. 2: 493-498. Graham, O. H. & J. L. Hourrigan. 1977. Eradication programs for the arthropod parasites of livestock. J. Med. Entomol. 13: 629-658. Harris, R. L., J. E. George, E. H. Ahrens, R. B. Davey & H. O. Bazan. 1988. Selection for resistance to coumaphos in a strain of southern cattle tick (Acari: Ixodidae). J. Econ. Entomol. 81: 545-548. Nolan, J., J. T. Wilson, P. E. Green & P. E. Bird. 1989. Synthetic pyrethroid resistance in field samples in the cattle tick (Boophilus microplus). Aust. Vet. J. 66: 179-182. SAS Institute. 1985. SAS/STAT guide for personal computers, version 6 ed. SAS Institute, Cary, NC. Steel, R.G.D. & J. H. Torrie. 1960. Principals and procedures of statistics. McGraw-Hill, New York. Stendel, W. 1985. Experimental studies on the tickicidal effect of Bayticol pour-on. Vet. Med. Rev. 2: 99-111. 1986. Studies on the distribution of flumethrin pour-on on the skin surface and the haircoat of cattle. Vet. Med. Rev. 1: 28-33. Stubbs, V. K., C. Wilshire & L. G. Webber. 1982. Cyhalothrin—A novel acaricidal and insecticidal synthetic pyrethroid for the control of the cattle tick (Boophilus microplus) and the buffalo fly (Haematobia irritans exigua). Aust. Vet. J. 59: 152-155. World Health Organization (WHO). 1990. Environmental health criteria 99: cyhalothrin. Geneva. Received for publication 3 March 1992; accepted 6 July 1992.
Downloaded from http://jee.oxfordjournals.org/ by guest on April 12, 2016
ing that coumaphos is 100% effective against the immature stages of B. microplus ticks. This distinction is important. Maximum efficacy of an acaricide is critical in an eradication program because, under present conditions, cattle infested with B. microplus can be moved into or within the United States 7 d after treatment with coumaphos. The results of our study suggest that cyhalothrin and lambdacyhalothrin would be efficacious in a control program where reduction in tick burden is the objective. However, these acaricides would be unsatisfactory in an eradication program where total elimination of parasitic ticks is the goal. Overall control with the 0.01% (AI) concentration of lambdacyhalothrin may reach >99%, but this is not the only criterion for efficacy of an acaricide. Other factors determine effectiveness of a compound, including the quantity of eggs produced by treated females, the hatch of eggs from treated females, and the length of time female ticks continue to feed on cattle after treatment. In terms of these latter factors, cyhalothrin and lambdacyhalothrin may not be good candidates for an eradication program.
Vol. 85, no. 6
