VECTOR CONTROL,PEST MANAGEMENT,RESISTANCE,REPELLENTS Effect of Prescribed Fire for Tick Control in California Chaparral K. A. PADGETT, 1 L. E. CASHER, 2 S. L. STEPHENS, 3 AND R. S. LANE 3 J. Med. Entomol. 46(5): 1138Ð1145 (2009) ABSTRACT Prescribed Þre was investigated as a method for controlling ixodid and argasid ticks in chaparral habitats in northern California. Two experimental and two adjacent control plots within a wildlife preserve were monitored for 1 yr postburn. Ticks were collected by ßagging vegetation, by CO 2 -baited pitfall trap, and by live-trapping rodents. Twice as many rodents were caught at control sites compared with burn sites and no dusky-footed woodrats, Neotoma fuscipes Baird, were found in the treatment sites postburn. This species is known to be a reservoir of the agents of Lyme disease, Borrelia burgdorferi sensu stricto Johnson, Schmid, Hyde, Steigerwalt & Brenner, and human gran- ulocytic anaplasmosis, Anaplasma phagocytophilum Dumler, Barbet, Bekker, Dasch, Palmer, Ray, Rikihisa, Rurangirwa. Six ixodid tick species were removed from rodents (Ixodes pacificus Cooley & Kohls, Ixodes jellisoni Cooley & Kohls, Ixodes spinipalpis Hadwen & Nuttall, Ixodes woodi Bishopp, Dermacentor occidentalis Marx, and Dermacentor parumapertus Neumann), two of which transmit bacterial zoonotic agents to people in the far-western United States. There was no decrease in number of ticks per animal trapped at either burn site compared with controls; in fact, the mean number of immature I. pacificus per rodent was signiÞcantly higher at one burn site than its control site. Soil refugia may protect ticks from Þre-induced mortality; the argasid tick Ornithodoros coriaceus Koch, which lives in soil, was unaffected by the prescribed Þre as were I. pacificus and D. occidentalis buried in packets 2.5 cm below ground. We conclude that although prescribed Þres in chaparral habitats may diminish local rodent abundance, it does not decrease tick loads on rodents. Furthermore, burning chaparral does not result in a decreased abundance of adult ixodid ticks on vegetation and apparently does not affect argasid or ixodid ticks that are sheltered within soil refugia. KEY WORDS tick control, Þre ecology, chaparral, Ixodes pacificus, Dermacentor occidentalis Tick-control methods tailored to the diverse ecology and land use of western North America are limited. Although application of acaricides to vegetation (Monsen et al. 1999) or host-targeted methods (Lane et al. 1998) has proven effective in reducing ticks locally, these methods generally are not used in Cal- ifornia. Prescribed burns have been shown to reduce the abundance of blacklegged ticks, Ixodes scapularis Say, locally, but the tick populations seem to rebound after 1 yr (Wilson 1986, Mather et al. 1993, Stafford et al. 1998). In western North America, summer wild- Þres are a part of the underlying ecology and pre- scribed burns are commonly employed for land-man- agement purposes (Biswell 1989, Husari et al. 2006). Chaparral is a common plant community throughout much of California and Baja Mexico and is one of the most ßammable plant communities in North America (Bolsinger 1989). To date, no study has investigated the effect of wild or prescribed burning on tick abundance in any hab- itat type in western North America. The two most commonly encountered ticks in this region are the western blacklegged tick, Ixodes pacificus Cooley & Kohls, and the PaciÞc Coast tick, Dermacentor occi- dentalis Marx. I. pacificus is an important vector of Borrelia burgdorferi sensu stricto Johnson, Schmid, Hyde, Steigerwalt & Brenner, the agent of lyme dis- ease in North America (Burgdorfer et al. 1985) as well as Anaplasma phagocytophilum Dumler, Barbet, Bek- ker, Dasch, Palmer, Ray, Rikihisa, Rurangirwa, the agent of human granulocytic anaplasmosis (Richter et al. 1996). Other nonhuman biting Ixodes species found in chaparral, such as Ixodes spinipalpis Hadwen & Nuttall and Ixodes jellisoni Cooley & Kohls, have been shown to be competent enzootic vectors of B. burg- dorferi sensu lato group spirochetes (Brown and Lane 1992, Lane et al. 1999, Brown et al. 2006). D. occiden- talis transmits Francisella tularensis McCoy and Chapin and has been shown to harbor pathogenic spotted fever group Rickettsia such as Rickettsia rick- ettsii and Rickettsia 364D (Philip et al. 1981, Wikswo et al. 2008). The Pajahuello tick, Ornithodoros coriaceus Koch, a common argasid tick throughout California oak (Quercus spp.) woodlands and chaparral habitats 1 Corresponding author: Vector-Borne Disease Section, California Department of Public Health, 850 Marina Bay Pkwy., Richmond, CA 94707 (e-mail: kerry.padgett@cdph.ca.gov). 2 UC Berkeley Upward Bound Math/Science Regional Center, 2150 Kittredge St., Suite 2C, Berkeley, CA 94704. 3 Department of Environmental Science, Policy, and Management, 137 Mulford Hall, University of California, Berkeley, CA 94720. 0022-2585/09/1138Ð1145$04.00/0  2009 Entomological Society of America