Kathleen R Walker

Interests

Research

Mosquito Ecology, Science Learning

Teaching

Insect Biology, Science Outreach, Agro-ecology

Courses

Scholarly Contributions

Journals/Publications

• Brophy, M., Riehle, M. A., Mastrud, N., Ravenscraft, A., Adamson, J. E., & Walker, K. R. (2022). Genetic Variation in s.l. Ticks across Arizona. International journal of environmental research and public health, 19(7).
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  s.l. (Latreille, 1806), the brown dog tick, is the most widely distributed tick species in the world. The two dominant lineages, a temperate group and a tropical group, are recognized as important disease vectors for both dogs and humans. The temperate and tropical lineages overlap in range in some regions of the world, including the southwestern United States, where recent outbreaks of Rocky Mountain spotted fever are linked to s.l. While it is unclear to what extent they may differ in their capacity to transmit pathogens, finer-scale resolution of temperate and tropical lineage distribution may provide insight into the ecology of these two tick groups and the epidemiology of s.l.-vectored diseases. Using diagnostic polymerase chain reaction assays, we examined the geospatial trends in s.l. lineages throughout Arizona. We found the temperate and tropical lineages were well delineated, with some overlap in the eastern part of the state. In one county, tropical and temperate ticks were collected on the same dog host, demonstrating that the two lineages are living in sympatry in some instances and may co-feed on the same host.
• Brophy, M., Walker, K. R., Adamson, J. E., & Ravenscraft, A. (2022). Tropical and Temperate Lineages of Rhipicephalus sanguineus s.l. Ticks (Acari: Ixodidae) Host Different Strains of Coxiella-like Endosymbionts. Journal of medical entomology, 59(6), 2022-2029.
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  Nonpathogenic bacteria likely play important roles in the biology and vector competence of ticks and other arthropods. Coxiella, a gram-negative gammaproteobacterium, is one of the most commonly reported maternally inherited endosymbionts in ticks and has been associated with over 40 tick species. Species-specific Coxiella-like endosymbionts (CLEs) have been reported in the brown dog tick, Rhipicephalus sanguineus sensu lato (Acari: Ixodidae), throughout the world, while recent research suggests low Coxiella diversity among tick species. We investigated CLE diversity among R. sanguineus s.l. ticks across Arizona. We detected 37 recurrent sequence variants (SVs) of the symbiont, indicating greater diversity in these symbiotic bacteria than previously reported. However, two SVs accounted for the vast majority of 16S rRNA amplicon reads. These two dominant CLEs were both closely related to Candidatus C. mudrowiae, an identified symbiont of Rhipicephalus turanicus ticks. One strain strongly associated with the tropical lineage of R. sanguineus s.l. while the other was found almost exclusively in the temperate lineage, supporting the conclusion that CLEs are primarily vertically transmitted. However, occasional mismatches between tick lineage and symbiont SV indicate that horizontal symbiont transfer may occur, perhaps via cofeeding of ticks from different lineages on the same dog. This study advances our understanding of CLE diversity in Rh. sanguineus s.l.
• Joy, T., Chen, M., Arnbrister, J., Williamson, D., Li, S., Nair, S., Brophy, M., Garcia, V. M., Walker, K., Ernst, K., Gouge, D. H., Carrière, Y., & Riehle, M. A. (2022). Assessing Near-Infrared Spectroscopy (NIRS) for Evaluation of Population Age Structure. Insects, 13(4).
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  Given that older (L.) mosquitoes typically pose the greatest risk of pathogen transmission, the capacity to age grade wild mosquito populations would be a valuable tool in monitoring the potential risk of arboviral transmission. Here, we compared the effectiveness of near-infrared spectroscopy (NIRS) to age grade field-collected with two alternative techniques-parity analysis and transcript abundance of the age-associated gene . Using lab-reared mosquitoes of known ages from three distinct populations maintained as adults under laboratory or semi-field conditions, we developed and validated four NIRS models for predicting the age of field-collected . To assess the accuracy of these models, female mosquitoes were collected from Maricopa County, AZ, during the 2017 and 2018 monsoon season, and a subset were age graded using the three different age-grading techniques. For both years, each of the four NIRS models consistently graded parous mosquitoes as significantly older than nulliparous mosquitoes. Furthermore, a significant positive linear association occurred between and NIRS age predictions in seven of the eight year/model combinations, although considerable variation in the predicted age of individual mosquitoes was observed. Our results suggest that although the NIRS models were not adequate in determining the age of individual field-collected mosquitoes, they have the potential to quickly and cost effectively track changes in the age structure of populations across locations and over time.
• Jeffrey Gutiérrez, E., Walker, K. R., Ernst, K. C., Riehle, M. A., & Davidowitz, G. (2019). Size as a Proxy for Longevity in Aedes aegypti (Diptera: Culicidae) Mosquitoes. Journal of Medical Entomology.
• Reyes-Castro, P., Ernst, K. C., Walker, K. R., Hayden, M., & Alvarez-Hernandez, G. (2021). Knowledge, Attitudes, and Practices Related to Rocky Mountain Spotted Fever in Hermosillo, México. Am J Trop Med Hyg ., 104(1), 184-189. doi:10.4269/ajtmh.20-0181
• Riehle, M. A., Walker, K. R., Ernst, K. C., Carriere, Y., Zinna, R., & Comeau, G. (2018). Impact of Zika virus vertical transmission in the mosquito Aedes aegypti. Emerging Infectious Diseases.
• Comeau, G., Zinna, R., Carriere, Y., Ernst, K. C., Walker, K. R., & Riehle, M. A. (2020). Impact of Zika virus vertical transmission in the mosquito Aedes aegypti. American Journal of Tropical Medicine and Hygiene, 103(2), 876-883. doi:10.4269/ajtmh.19-0698
• Davidowitz, G., Riehle, M. A., Ernst, K. C., Walker, K. R., & Jeffrey Gutierrez, E. (2020). Size as a Proxy for Longevity in Aedes aegypti (Diptera: Culicidae) Mosquitoe. Journal of Medical Entomology, 57, 1228-1238.
• Davidowitz, G., Riehle, M. A., Ernst, K. C., Walker, K. R., & Jeffrey Gutiérrez, E. (2020). Size as a Proxy for Longevity in Aedes aegypti (Diptera: Culicidae) Mosquitoes. Journal of Medical Entomology.
• Jeffrey Gutierrez, E., Walker, K. R., Ernst, K. C., Riehle, M. A., & Davidowitz, G. (2020). Size as a Proxy for Longevity in Aedes aegypti (Diptera: Culicidae) Mosquitoe. Journal of Medical Entomology, 57(4), 1228-1238. doi:10.1093/jme/tjaa055
• Casal, M. G., Walker, K. R., Yaglom, H. D., Weiss, J., Walker, K. R., Venkat, H., Tarter, K. D., Stokka, D., Rathman, R., Plante, L., Levy, C. E., Gouge, D. H., Casal, M. G., & Adams, L. E. (2019). USING CITIZEN SCIENCE TO ENHANCE SURVEILLANCE OF AEDES AEGYPTI IN ARIZONA, 2015-17.. Journal of the American Mosquito Control Association, 35(1), 11-18. doi:10.2987/18-6789.1
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  Vector surveillance is an essential component of vector-borne disease prevention, but many communities lack resources to support extensive surveillance. The Great Arizona Mosquito Hunt (GAMH) was a collaborative citizen science project conducted during 2015-17 to enhance surveillance for Aedes aegypti in Arizona. Citizen science projects engage the public in scientific research in order to further scientific knowledge while improving community understanding of a specific field of science and the scientific process. Participating schools and youth organizations across the state conducted oviposition trapping for 1-4 wk during peak Ae. aegypti season in Arizona and returned the egg sheets to collaborating entomologists for identification. During the 3-year program, 120 different schools and youth organizations participated. Few participants actually collected Aedes eggs in their traps in 2015 or 2017, but about one-third of participants collected eggs during 2016, including 3 areas that were not previously reported to have Ae. aegypti. While relatively few new areas of Ae. aegypti activity were identified, GAMH was found to be a successful method of engaging citizen scientists. Future citizen science mosquito surveillance projects might be useful to further define the ecology and risk for vector-borne diseases in Arizona.
• Walker, K. R., Venkat, H., Weiss, J., Stokka, D., Rathman, R., Gouge, D. H., Casal, M., Plante, L. M., Adams, L., Yaglom, H., Levy, C., & Tarter, K. (2019). Using Citizen Science to Enhance Surveillance of the Mosquito Vector Aedes aegypti in Arizona. Journal of the American Mosquito Control Association.
• Walker, K. R., Williamson, D. J., Walker, K. R., Reyes-castro, P. A., Hayden, M. H., Haenchen, S., Gutierrez, E. J., Ernst, K. C., & Carriere, Y. (2018). Socioeconomic and Human Behavioral Factors Associated With Aedes aegypti (Diptera: Culicidae) Immature Habitat in Tucson, AZ.. Journal of medical entomology, 55(4), 955-963. doi:10.1093/jme/tjy011
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  Aedes aegypti (L.; Diptera: Culicidae) has been established in the southwestern United States for several decades, but relationships between humans and mosquitoes in this arid region are not well-characterized. In August 2012, the outdoor premises of 355 houses within 20 neighborhoods in Tucson, Arizona were surveyed for containers that could provide larval habitat for Ae. aegypti mosquitoes. At the same time, a knowledge, attitudes and practices (KAP) questionnaire was administered to a resident of each house surveyed for immature mosquitoes. The KAP questionnaire assessed respondents' knowledge and concerns about vector-borne illnesses as well as practices they used to avoid mosquitoes. Of the houses surveyed, 91% had at least one container present, and 64% had at least one container with standing water. On average, each house had 2.2 containers with water at the time of the survey. The overall House Index (proportion of premises surveyed with at least one container with Ae. aegypti immatures present) was 13%. Based on questionnaire responses, there was a significant positive association between the number of residents in the home and the odds of finding Ae. aegypti positive containers on the premises, while household income showed a significant negative association. The reported frequency of checking for standing water was also significantly associated with the odds of finding immatures, although the nature of this association was ambiguous. Flower pots were the principal type of container with Ae. aegypti larvae. These findings show that larval habitat is widely available even in an arid environment and city with good housing and sanitation infrastructure.
• Walker, K. R., Williamson, D., Carriere, Y., Reyes Castro, P., Hanechen, S., Hayden, M., Jeffrey Guttierez, E., & Ernst, K. C. (2017). Socioeconomic and human behavioral factors associated with Aedes aegypti (Diptera: Culicidae) immature habitat in Tucson, AZ. Journal of Medical Entomology.
• Casal, M. G., Casal, M. G., Dent, N., Arriola, J., Dominguez, V., Lueck, E., Gentzsch, G., Walker, K., Guerrero, R., & Jacobs, S. J. (2017). Enhanced Aedes spp. surveillance across jurisdictions in Arizona’s border region. Online Journal of Public Health Informatics, 9(1). doi:10.5210/ojphi.v9i1.7682
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  Objective This surveillance project aims to increase and broaden coverage of Aedes spp. ovitrap locations in Arizona’s U.S.-Mexico border region through interagency collaboration. Introduction As part of a statewide effort to enhance surveillance for Aedes spp. mosquitoes (1,2) the Office of Border Health (OBH) took the lead in providing technical assistance on surveillance in counties bordering Mexico. In 2016, OBH sought ways to enhance surveillance in a wider geographic area. Trap locations closer to the border were established as a priority, given high amount of traffic across the international line, high border Aedes mosquito activity, and native cases of dengue reported at the border in Mexico. Methods The Arizona Office of Border Health partnered with U.S. Customs and Border Protection to select possible locations for ovitrapping near the border. Border Patrol Health and Safety Tucson coordination accompanied OBH and preparedness staff on three occasions to scout areas around pre-selected border patrol facilities. County, and border patrol staff contributed to trap maintenance. BIDS provided technical assistance to identify positive traps, collected data for reporting to the state, and collaborated with experts at the University of Arizona entomology department to verify results and identify Aedes spp. Results Out of 15 border patrol stations within border lands in Santa Cruz County, and Cochise County, OBH epidemiologist considered 10 viable trapping sites. Two facilities were eventually eliminated because of logistical challenges. OBH visited eight facilities and selected five locations within five miles of the U.S. –Mexico border and two located less than 30 miles from the border. OBH epidemiologists inspected sites for potential mosquito habitat and set ovitraps low to the ground in areas protected from rain. Some facilities had areas of standing water discovered in unused tires, truck-washing stations, heavy-lifting equipment, and natural washes. Border Patrol staff complained of mosquito activity around some of the stations. After inspection OBH set an average of three traps at each site. One site had evidence of mosquito larvae activity. Conclusions Border patrol facilities offer ideal trap locations given their proximity to the international line. Secure facilities offer extra protection for traps against tampering. The partnership across local, state, tribal, and federal lines allowed Arizona Office of Border Health to expand surveillance locations, allowing two jurisdictions to set the first Aedes-specific traps since Arizona began the 2016 campaign, “Fight the Bite.”
• Castro-Reyes, P., Luque-Castro, A. L., Diaz-Caravantes, R., Walker, K. R., Hayden, M., & Ernst, K. C. (2016). Outdoor Spatial Spraying Against Dengue: A False Sense of Security Among Inhabitants of Hermosillo, Mexico.. PLoS Neglected Tropical Diseases.
• Walker, K. R., Walker, K. R., Reyes-castro, P. A., Hayden, M. H., Ernst, K. C., Diaz-caravantes, R. E., & Castro-luque, L. (2017). Outdoor spatial spraying against dengue: A false sense of security among inhabitants of Hermosillo, Mexico.. PLoS neglected tropical diseases, 11(5), e0005611. doi:10.1371/journal.pntd.0005611
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  Government-administered adulticiding is frequently conducted in response to dengue transmission worldwide. Anecdotal evidence suggests that spraying may create a "false sense of security" for residents. Our objective was to determine if there was an association between residents' reporting outdoor spatial insecticide spraying as way to prevent dengue transmission and both their reported frequency of dengue prevention practices and household entomological indices in Hermosillo, Mexico..A non-probabilistic survey of 400 households was conducted in August 2014. An oral questionnaire was administered to an adult resident and the outer premises of the home were inspected for water-holding containers and presence of Ae. aegypti larvae and pupae. Self-reported frequency of prevention practices were assessed among residents who reported outdoor spatial spraying as a strategy to prevent dengue (n = 93) and those who did not (n = 307). Mixed effects negative binomial regression was used to assess associations between resident's reporting spraying as a means to prevent dengue and container indices. Mixed effects logistic regression was used to determine associations with presence/absence of larvae and pupae. Those reporting spatial spraying disposed of trash less frequently and spent less time indoors to avoid mosquitoes. They also used insecticides and larvicides more often and covered their water containers more frequently. Their backyards had more containers positive for Ae. aegypti (RR = 1.92) and there was a higher probability of finding one or more Ae. aegypti pupae (OR = 2.20). Survey respondents that reported spatial spraying prevented dengue were more likely to be older and were exposed to fewer media sources regarding prevention..The results suggest that the perception that outdoor spatial spraying prevents dengue is associated with lower adoption of prevention practices and higher entomological risk. This provides some support to the hypothesis that spraying may lead to a "false sense of security". Further investigations to clarify this relationship should be conducted. Government campaigns should emphasize the difficulty in controlling Ae. aegypti mosquitoes and the need for both government and community action to minimize risk of dengue transmission.
• Casal, M. G., Walker, K., Walker, K., Jacobs, S. J., Hayden, M. K., Ernst, K. C., Erly, S., Dent, N., Casal, M. G., & Arriola, J. (2016). Enhanced Mosquito Surveillance for Aedes spp. in Santa Cruz County, Arizona. Online Journal of Public Health Informatics, 8(1). doi:10.5210/ojphi.v8i1.6465
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  This project was developed to enhance surveillance for Aedes spp. mosquitoes in an Arizona border county. The county mantained 11 trapping sites and we enrolled community members to help as a citizen science effort, adding over 40 trapping sites to the project. We aim to determine presence, absence, distribution and seasonality of the vector by using ovitraps that are well-distributed in the community.
• Dickinson, K., Hayden, M., Haenchen, S., Monaghan, A., Walker, K. R., & Ernst, K. C. (2015). Willingness to Pay for Mosquito Control in Key West, Florida, and Tucson, Arizona. American Journal of Tropical Medicine and Hygiene.
• Ernst, K. C., Walker, K. R., Reyes-Castro, P., Joy, T. K., Castro-Luque, A. L., Diaz-Caravantes, R., Gameros, M., Haenchen, S., Hayden, M., Monaghan, A., Jeffrey Guttierez, E., Carriere, Y., & Riehle, M. A. (2016). Aedes aegypti (Diptera: Culicidae) Longevity and Differential Emergence of Dengue Fever in Two Cities in Sonora, Mexico. Journal of Medical Entomology.
• Haenchen, S., Hayden, M., Dickinson, K., Walker, K. R., Jacobs, E. T., Brown, H. E., Gunn, J., Kohler, L., & Ernst, K. C. (2015). Mosquito avoidance practices and knowledge of arboviral diseases in cities with differing recent history of disease. American Journal of Tropical Medicine and Hygiene.
• Walker, K. R., Walker, K. R., Monaghan, A. J., Hayden, M. H., Haenchen, S., Ernst, K. C., & Dickinson, K. L. (2016). Willingness to Pay for Mosquito Control in Key West, Florida and Tucson, Arizona.. The American journal of tropical medicine and hygiene, 94(4), 775-9. doi:10.4269/ajtmh.15-0666
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  Mosquito-borne illnesses like West Nile virus (WNV) and dengue are growing threats to the United States. Proactive mosquito control is one strategy to reduce the risk of disease transmission. In 2012, we measured the public's willingness to pay (WTP) for increased mosquito control in two cities: Key West, FL, where there have been recent dengue outbreaks, and Tucson, AZ, where dengue vectors are established and WNV has been circulating for over a decade. Nearly three quarters of respondents in both cities (74% in Tucson and 73% in Key West) would be willing to pay $25 or more annually toward an increase in publicly funded mosquito control efforts. WTP was positively associated with income (both cities), education (Key West), and perceived mosquito abundance (Tucson). Concerns about environmental impacts of mosquito control were associated with lower WTP in Key West. Expanded mosquito control efforts should incorporate public opinion as they respond to evolving disease risks.
• Walker, K., Gunn, J. K., Walker, K., Kohler, L. N., Jacobs, E. E., Hayden, M. H., Haenchen, S. D., Gunn, J. K., Ernst, K. C., Dickinson, K. L., & Brown, H. E. (2016). Mosquito Avoidance Practices and Knowledge of Arboviral Diseases in Cities with Differing Recent History of Disease.. The American journal of tropical medicine and hygiene, 95(4), 945-953. doi:10.4269/ajtmh.15-0732
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  As the range of dengue virus (DENV) transmission expands, an understanding of community uptake of prevention and control strategies is needed both in geographic areas where the virus has recently been circulating and in areas with the potential for DENV introduction. Personal protective behaviors such as the use of mosquito repellent to limit human-vector contact and the reduction of vector density through elimination of oviposition sites are the primary control methods for Aedes aegypti, the main vector of DENV. Here, we examined personal mosquito control measures taken by individuals in Key West, FL, in 2012, which had experienced a recent outbreak of DENV, and Tucson, AZ, which has a high potential for introduction but has not yet experienced autochthonous transmission. In both cities, there was a positive association between the numbers of mosquitoes noticed outdoors and the overall number of avoidance behaviors, use of repellent, and removal of standing water. Increased awareness and perceived risk of DENV were associated with increases in one of the most effective household prevention behaviors, removal of standing water, but only in Key West.
• Ernst, K. C., Haenchen, S., Dickinson, K., Doyle, M., Walker, K. R., Monaghan, A., & Hayden, M. (2015). Awareness and Support of Release of Genetically Modified “Sterile” Mosquitoes, Key West, Florida, USA. Emerging Infectious Diseases, 21(2).
• Walker, K., Riehle, M. A., Walker, K., Riehle, M. A., Monaghan, A. J., Hayden, M. H., Haenchen, S., Ernst*, K. C., Ernst, K. C., Castro-reyes, P., Castro, L., & Caravantes, R. (2014). Differential Emergence of Dengue in the Arizona-Sonora Desert Region: Understanding the Role of Social and Environmental Factors. ISEE Conference Abstracts, 2014(1), 3011. doi:10.1289/isee.2014.s-053
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  Following the collapse of the Ae. aegypti control programs in the late 1960’s Ae. aegypti re-established itself across much of the tropics and sub-tropics in the Americas. Dengue soon emerged in ma...
• Joy, T. K., H., E., Ernst, K., Walker, K. R., Carriere, Y., Torabi, M., & Riehle, M. A. (2012). Aging Field Collected Aedes aegypti to Determine Their Capacity for Dengue Transmission in the Southwestern United States. PLoS ONE, 7(10).
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  PMID: 23077536;PMCID: PMC3470585;Abstract: Aedes aegypti, the primary vector of dengue virus, is well established throughout urban areas of the Southwestern US, including Tucson, AZ. Local transmission of the dengue virus, however, has not been reported in this area. Although many factors influence the distribution of the dengue virus, we hypothesize that one contributing factor is that the lifespan of female Ae. aegypti mosquitoes in the Southwestern US is too short for the virus to complete development and be transmitted to a new host. To test this we utilized two age grading techniques. First, we determined parity by analyzing ovarian tracheation and found that only 40% of Ae. aegypti females collected in Tucson, AZ were parous. The second technique determined transcript levels of an age-associated gene, Sarcoplasmic calcium-binding protein 1 (SCP-1). SCP-1 expression decreased in a predictable manner as the age of mosquitoes increased regardless of rearing conditions and reproductive status. We developed statistical models based on parity and SCP-1 expression to determine the age of individual, field collected mosquitoes within three age brackets: nonvectors (0-5 days post-emergence), unlikely vectors (6-14 days post-emergence), and potential vectors (15+ days post-emergence). The statistical models allowed us to accurately group individual wild mosquitoes into the three age brackets with high confidence. SCP-1 expression levels of individual, field collected mosquitoes were analyzed in conjunction with parity status. Based on SCP-1 transcript levels and parity data, 9% of collected mosquitoes survived more than 15 days post emergence. © 2012 Joy et al.
• Walker, K. R., Joy, T., Jeffrey, G. E., Ernst, K., Walkerv, K. R., Carriere, Y., Torabi, M., & Riehle, M. A. (2012). Aging Field Collected Aedes aegypti to Determine Their Capacity for Dengue Transmission in the Southwestern United States. PLoS One, 7(10).
• Walker, K. R., Joy, T. K., Ellers-Kirk, C., & Ramberg, F. B. (2011). Human and environmental factors affecting aedes aegypti distribution in an arid urban environment. Journal of the American Mosquito Control Association, 27(2), 135-141.
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  PMID: 21805845;Abstract: Aedes aegypti has reappeared in urban communities in the southwestern USA in the 1990s after a 40-year absence. In 2003 and 2004, a systematic survey was conducted throughout metropolitan Tucson, AZ, to identify human and environmental factors associated with Ae. aegypti distribution within an arid urban area. Aedes aegypti presence and abundance were measured monthly using the Centers for Disease Control and Prevention enhanced oviposition traps at sampling sites established in a grid at 3-to 4-km intervals across the city. Sampling occurred in the summer rainy season (July through September), the peak of mosquito activity in the region. Multiple regression analyses were conducted to determine relationships between mosquito density and factors that could influence mosquito distribution. House age was the only factor that showed a consistent significant association with Ae. aegypti abundance in both years: older houses had more mosquito eggs. This is the 1st study of Ae. aegypti distribution at a local level to identify house age as an explanatory factor independent of other human demographic factors. Further research into the reasons why mosquitoes were more abundant around older homes may help inform and refine future vector surveillance and control efforts in the event of a dengue outbreak in the region. © 2011 by the American Mosquito Control Association, Inc.
• Walker, K., Joy, T., Ellers-Kirk, C., & Ramberg, F. (2011). Human and Environmental Factors Affecting Aedes aegypti distribution in an arid urban environment. Journal of the American Mosquito Control Association.
• Hayden, M. H., Uejio, C. K., Walker, K., Ramberg, F., Moreno, R., Rosales, C., Gameros, M., Mearns, L. O., Zielinski-Gutierrez, E., & Janes, C. R. (2010). Microclimate and human factors in the divergent ecology of aedes aegypti along the Arizona, U.S./Sonora, MX border. EcoHealth, 7(1), 64-77.
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  PMID: 20232228;Abstract: This study examined the association of human and environmental factors with the presence of Aedes aegypti, the vector for dengue fever and yellow fever viruses, in a desert region in the southwest United States and northwest Mexico. Sixty-eight sites were longitudinally surveyed along the United States-Mexico border in Tucson, AZ, Nogales, AZ, and Nogales, Sonora during a 3-year period. Aedes aegypti presence or absence at each site was measured three times per year using standard oviposition traps. Maximum and minimum temperature and relative humidity were measured hourly at each site. Field inventories were conducted to measure human housing factors potentially affecting mosquito presence, such as the use of air-conditioning and evaporative coolers, outdoor vegetation cover, and access to piped water. The results showed that Ae. aegypti presence was highly variable across space and time. Aedes aegypti presence was positively associated with highly vegetated areas. Other significant variables included microclimatic differences and access to piped water. This study demonstrates the importance of microclimate and human factors in predicting Ae. aegypti distribution in an arid environment. © 2010 International Association for Ecology and Health.
• Walker, K., & Lynch, M. (2007). Contributions of Anopheles larval control to malaria suppression in tropical Africa: Review of achievements and potential. Medical and Veterinary Entomology, 21(1), 2-21.
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  PMID: 17373942;Abstract: Malaria vector control targeting the larval stages of mosquitoes was applied successfully against many species of Anopheles (Diptera: Culicidae) in malarious countries until the mid-20th Century. Since the introduction of DDT in the 1940s and the associated development of indoor residual spraying (IRS), which usually has a more powerful impact than larval control on vectorial capacity, the focus of malaria prevention programmes has shifted to the control of adult vectors. In the Afrotropical Region, where malaria is transmitted mainly by Anopheles funestus Giles and members of the Anopheles gambiae Giles complex, gaps in information on larval ecology and the ability of An. gambiae sensu lato to exploit a wide variety of larval habitats have discouraged efforts to develop and implement larval control strategies. Opportunities to complement adulticiding with other components of integrated vector management, along with concerns about insecticide resistance, environmental impacts, rising costs of IRS and logistical constraints, have stimulated renewed interest in larval control of malaria vectors. Techniques include environmental management, involving the temporary or permanent removal of anopheline larval habitats, as well as larviciding with chemical or biological agents. This present review covers large-scale trials of anopheline larval control methods, focusing on field studies in Africa conducted within the past 15 years. Although such studies are limited in number and scope, their results suggest that targeting larvae, particularly in human-made habitats, can significantly reduce malaria transmission in appropriate settings. These approaches are especially suitable for urban areas, where larval habitats are limited, particularly when applied in conjunction with IRS and other adulticidal measures, such as the use of insecticide treated bednets. © 2007 The Authors.
• Walker, K. R., & Welter, S. C. (2004). Biological control potential of Apanteles aristoteliae (Hymenoptera: Braconidae) on populations of Argyrotaenia citrana (Lepidoptera: Tortricidae) in California apple orchards. Environmental Entomology, 33(5), 1327-1334.
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  Abstract: This study examined the potential role of native parasitoids in suppressing pest populations of Argyrotaenia citrana (Fernald) in coastal California apple orchards. An initial survey of larval and pupal parasitoids of A. citrana found that the most common parasitoids of A. citrana were the braconid Apanteles aristoteliae Viereck and the ichneumonid Exochus nigripalpis subobscurus Walsh that together parasitized 33% of the A. citrana larvae collected. To identify which parasitoid species caused most host mortality, parasitoid-induced mortality was examined more closely using sentinel A. citrana larvae. Small batches of both newly hatched and older (third and fourth instars) larvae were released and recaptured to collect emerging parasitoids. The results suggested that most parasitoid-induced mortality occurred in young larvae attacked by A. aristoteliae. To determine whether A. aristoteliae would be likely to suppress A. citrana populations in apples, further release-recapture experiments were conducted to assess the parasitoid's response to host aggregation. A. citrana larvae were released into small patches (individual clusters of fruit) and larger patches (an entire tree) at varying densities. In both the cluster and tree scale experiments the percentage of larvae parasitized by A. aristoteliae remained fairly constant at 40% regardless of the number of host larvae in a patch. These results indicate that A. aristoteliae attacks A. citrana in a density independent manner, which suggests that this parasitoid alone does not exert a strong regulatory effect on summer populations of A. citrana in apples.
• Walker, K. R., Ricciardoneb, M. D., & Jensen, J. (2003). Developing an international consensus on DDT: A balance of environmental protection and disease control. International Journal of Hygiene and Environmental Health, 206(4-5), 423-435.
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  PMID: 12971698;Abstract: The Stockholm Convention on Persistent Organic Pollutants provides a framework for international action on 12 persistent, bioaccumulative and toxic chemicals of global concern. While production and use of most of the listed chemicals will shortly be eliminated, there is widespread agreement that DDT will continue to be needed for disease vector control. Science played a key role in informing policy makers from developed and developing countries who drafted the DDT provision of the convention. This paper examines both the science and the politics that contributed to an international consensus on DDT.
• Walker, K., Mendelsohn, M., Matten, S., Alphin, M., & Ave, D. (2003). The Role of Microbial Bt Products in U.S. Crop Protection. Journal of New Seeds, 5(1), 31-51.
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  Abstract: Microbial Bacillus thuringiensis (Bt) insecticides have been used for over 40 years. In the United States, Bt formulations are primarily applied to control lepidopteran pests on fruit and vegetable crops, to control gypsy moth in forests and to control dipteran pests (mosquitoes and blackflies) that bite humans. A highly selective insecticide with activity conferred primarily by insecticidal crystal proteins (ICPs), Bt is generally not harmful to humans, non-target wildlife or beneficial arthropods. Its selectivity and unique mode of action make it an important alternative to conventional chemical insecticides, and many integrated pest management (IPM) programs for particular fruit and vegetable crops as well as certified organic production include the use of Bt. Agricultural commercialization and adoption of plant-incorporated Bt presents new opportunities to expand the use of Bt ICPs for agricultural pest control, but also raises concerns about the potential for accelerated development of pest resistance to Bt. The relative risks and benefits of microbial and plant-incorporated Bt products are introduced. © 2003 by The Haworth Press, Inc. All rights reserved.
• Walker, K. R., & Welter, S. C. (2001). Potential for outbreaks of leafrollers (lepidoptera: tortricidae) in California apple orchards using mating disruption for codling moth suppression. Journal of Economic Entomology, 94(2), 373-380.
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  PMID: 11332828;Abstract: Two species of leafrollers, Argyrotaenia citrana (Fernald) and Pandemis pyrusana Kearfott, represent serious obstacles to the implementation of mating disruption for control of codling moth in coastal California apple orchards. Larval and adult densities of A. citrana and P. pyrusana and subsequent fruit damage were compared under different codling moth control treatments. Leafroller larval counts and levels of fruit damage were significantly higher in most plots that were untreated or treated only with codling moth pheromone. Leafroller fruit damage levels in these plots were commonly between 10 and 15% at harvest. As summer larval counts were good predictors of fruit damage levels, larval sampling could be a useful tool for predicting leafroller outbreaks. Use of pheromone trapping for A. citrana to detect localized outbreaks within an orchard was not useful and failed to correlate with larval numbers, whereas adult monitoring for P. pyrusana appears more promising. Efforts to implement a codling moth mating-disruption program in California must include changes in strategies for monitoring and controlling leafroller species. © 2001 Entomological Society of America.
• Walker, K. (2000). Cost-comparison of DDT and alternative insecticides for malaria control. Medical and Veterinary Entomology, 14(4), 345-354.
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  PMID: 11129697;Abstract: In anti-malaria operations the use of DDT for indoor residual spraying has declined substantially over the past 30 years, but this insecticide is still considered valuable for malaria control, mainly because of its low cost relative to alternative insecticides. Despite the development of resistance to DDT in some populations of malaria vector Anopheles mosquitoes (Diptera: Culicidae), DDT remains generally effective when used for house-spraying against most species of Anopheles, due to excitorepellency as well as insecticidal effects. A 1990 cost comparison by the World Health Organization (WHO) found DDT to be considerably less expensive than other insecticides, which cost 2 to 23 times more on the basis of cost per house per 6 months of control. To determine whether such a cost advantage still prevails for DDT, this paper compares recent price quotes from manufacturers and WHO suppliers for DDT and appropriate formulations of nine other insecticides (two carbamates, two organophosphates and five pyrethroids) commonly used for residual house-spraying in malaria control programmes. Based on these 'global' price quotes, detailed calculations show that DDT is still the least expensive insecticide on a cost per house basis, although the price appears to be rising as DDT production declines. At the same time, the prices of pyrethroids are declining, making some only slightly more expensive than DDT at low application dosages. Other costs, including operations (labour), transportation and human safety may also increase the price advantages of DDT and some pyrethroids vs. organophosphates and carbamates, although possible environmental impacts from DDT remain a concern. However, a global cost comparison may not realistically reflect local costs or effective application dosages at the country level. Recent data on insecticide prices paid by the health ministries of individual countries showed that prices of particular insecticides can vary substantially in the open market. Therefore, the most cost-effective insecticide in any given country or region must be determined on a case-by-case basis. Regional coordination of procurement of public health insecticides could improve access to affordable products.
• Walker, K. R., & Welter, S. C. (1999). Effects of lure dose on efficacy of pheromone traps for monitoring Argyrotaenia citrana (Lepidoptera: Tortricidae) in California apple orchards. Journal of Economic Entomology, 92(3), 574-582.
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  Abstract: This study tested lowering the lure dose of Argyrotaenia citrana (Fernald) pheromone to improve the accuracy of the traps as indicators of larval density (and subsequent fruit damage) within coastal California apple orchards. Different doses of pheromone ranging from 1 to 0.001 mg were tested in commercial apple orchards in 1994 and 1995. Mean weekly trap catches were significantly higher in higher dose traps. However, the proportion of moths caught in higher dose traps versus lower dose traps remained fairly constant within each orchard, suggesting that lower dose traps were attracting moths from the same regional pool of moths as the higher dose traps. No statistically significant relationships were detected between average weekly moth catches using each of the 4 lure doses and A. citrana larval counts in 1995. These results suggest that lowering lure dose will not improve the accuracy of pheromone traps as predictors of A. citrana larval density. The lack of correlations between larval densities and male moth counts is discussed relative to the need to monitor female flight activity.
• Walker, K., Vallero, D. A., & Lewis, R. G. (1999). Factors Influencing the Distribution of Lindane and Other Hexachlorocyclohexanes in the Environment. Environmental Science & Technology, 33(24), 4373-4378. doi:10.1021/es990647n
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  This review examines the potential for γ-hexachlorocyclohexane (HCH) to be transformed into other isomers of HCH. HCH residues are among the most widely distributed and frequently detected organochlorine contaminants in the environment. The potential environmental and human health risks associated with these residues have prompted Canada, the United States, and Mexico to consider the development of a North American Regional Action Plan (NARAP) to assess and mitigate HCH pollution. More information on the propensity of γ-HCH to transform into other isomers is essential to the development of an effective regional management program. The high relative concentrations of α-HCH in the Arctic suggest that γ-HCH may be transformed into other isomers in the environment. Laboratory studies show that significant photoisomerization of γ-HCH to α-HCH is possible. However, field studies do not find evidence for significant isomerization of γ-HCH, and recent environmental samples suggest that α-HCH residues are declinin...

Proceedings Publications

• Walker, K. (2016). Enlisting citizen scientists for disease vector surveillance: The great Arizona mosquito hunt. In 2016 International Congress of Entomology.

Presentations

• Teegerstrom, T., Ellsworth, P. C., Woolfolk, C. M., Weber, J. L., Nair, S., Ernst, K. C., Walker, K. R., Fournier, A. J., Gouge, D. H., & Li, S. (2021, October-November). Emergency Preparedness through Integrated Pest Management Education and Tribal Partnerships in Arizona. 2021 Entomological Society of America Annual Conference. Denver, CO..
• Nair, S., Arnbrister, J., Li, S., Williamson, D., Ernst, K. C., Riehle, M. A., Gouge, D. H., & Walker, K. R. (2020, November). Impacts of ULV adulticiding on the vectorial capacity of the Zika vector, Aedes aegypti. 2020 Entomology Virtual Annual Meeting. November 11 – 25, 2020.
• Teegerstrom, T., Ellsworth, P. C., Ernst, K. C., Walker, K. R., Brophy, M., Reese, S., Dorame-Avalos, A., Nair, S., Fournier, A. J., Gouge, D. H., & Li, S. (2020, November). Public Health IPM Education – Honoring and empowering tribal nations and indigenous peoples. 2020 Entomological Society of America Virtual Annual Meeting. November 11–25, 2020.
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  1220 views. On-demand presentation available for 3068 meeting registrants.
• Ellsworth, P. C., Fournier, A. J., Teegerstrom, T., Rivadeneira, P., Ernst, K. C., Walker, K. R., Brophy, M., Reese, S., Dorame-Avalos, A., Nair, S., Gouge, D. H., & Li, S. (2019, August). Effective Partnerships in Public Health IPM Education in American Indian Communities. National Environmental Health Association Integrated Pest Management Solutions in Environmental Health Virtual Conference. Virtual Conference: National Environmental Health Association.
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  158 views. 106 NEHA CEUs
• Fournier, A. J., Ellsworth, P. C., Teegerstrom, T., Rivadeneira, P., Ernst, K. C., Walker, K. R., Brophy, M., Reese, S., Dorame-Avalos, A., Nair, S., Gouge, D. H., & Li, S. (2019, 08-29-2019). Effective Partnerships in Public Health IPM Education in American Indian Communities. NEHA Pest-Control through Environmentally Sustainable Treatments (PEST) Virtual Conference, August 28-29, 2019.
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  158 participants. 106 NEHA CEUs.
• Fournier, A. J., Fournier, A. J., Ellsworth, P. C., Ellsworth, P. C., Teegerstrom, T., Teegerstrom, T., Rivadeneira, P., Rivadeneira, P., Ernst, K. C., Ernst, K. C., Walker, K. R., Walker, K. R., Brophy, M., Brophy, M., Reese, S., Reese, S., Dorame-Avalos, A., Dorame-Avalos, A., Nair, S., , Nair, S., et al. (2019, 10-22-2019). Effective Partnerships in IPM Education in Indian Communities. Tribal/EPA Region 9 Conference. Maricopa, AZ 85138. October 22-24, 2019..
• Walker, K. R., Riehle, M. A., & Ernst, K. C. (2019, July). Unravelling the social and biological determinants of arboviral transmission in the Arizona-Sonora border region.. 8th International Symposium on Insect Molecular Biology. Sitges, Spain.
• Ernst, K. C., Riehle, M. A., Walker, K. R., & Weitemier, T. D. (2018, October). Evidence and variation in nectar feeding from wild Aedes aegypti mosquitoes from an arid environment. Society of Vector Ecology. Yosemite, California.
• Reyes Castro, P., Walker, K. R., Castro Luque, A. L., & Ernst, K. C. (2017, Nov.). Datos de investigación y recomendaciones para la vigilancia y prevención del dengue.. Advisory meeting to the Secretaria de Salud, Estado de Sonora (Sonora State Health Department). Hermosillo, Sonora, Mexico: Foro Binacional, Estado de Sonora.
• Reyes Castro, P., Walker, K. R., Castro Luque, A. L., & Ernst, K. C. (2017, Nov.). On the edge: dengue and climate (in Spanish). Foro Binacional: Redes Regionales - Arizona, Sonora, California, Baja California. Hermosillo, Sonora, Mexico: Foro Binacional Redes Regionales - Arizona, Sonora, California, Baja California.
• Walker, K. R., Ernst, K. C., Riehle, M. A., Joy, T., & Reyes Castro, P. (2017, March). Ecology of Aedes aegypti and public perception of mosquitoes in the Arizona/Sonora border region. 2017 Arizona Vector Control Conference. Phoenix, AZ: Arizona Dept. of Health Services.
• Beal, B., & Walker, K. R. (2016, September). Science Outreach to Elementary Schools: Evaluating Impacts of the Insect Discovery Program.. International Congress of Entomology. Orlando, Florida,: International Congress of Entomology.
• Walker, K. R. (2016, November). Ecology of Aedes aegypti and arbovirus risk in the Arizona/Sonora border region. Monthly seminar. Arid Lands Research Center: USDA-ARS.
• Walker, K. R., Ernst, K. C., Castro-Reyes, P., & Riehle, M. A. (2016, October). Ecologia de Aedes aegypti y el Riesgo de Dengue en la Region de Arizona/Sonora [in Spanish]. Simposio Binacional: Exploracion de los Aspectos Ambientales y de Salud del Zika, Dengue Chikungunya y la Fiebre Manchada,. Nogales, Sonora: U.S. EPA.
• Walker, K. R., Joy, T. K., Ernst, K. C., Riehle, M. A., & Daniel, W. (2016, September). Understanding the Zika vector in the desert southwest.. Science Café –. Tucson, AZ: Southwest Environmental Health Sciences Center, University of Arizona.
• Walker, K. R., Joy, T. K., Ernst, K. C., Riehle, M. A., & Daniel, W. (2016, September). Understanding the Zika vector in the desert southwest.. Volunteer Leadership Engagement Day with the Wildcat for Life and National Leadership Councils. Tucson, AZ: University of Arizona.
• Walker, K. R., Rathman, R., Yaglom, H., Levy, C., Beal, B., Ernst, K. C., Casal, M., & Stokka, D. (2016, September). Enlisting citizen scientists for disease vector surveillance: The Great Arizona Mosquito Hunt.. International Congress of Entomology. Orlando, Florida,: International Congress of Entomology.
• Walker, K. R., & Ernst, K. C. (2015, July). Factores que influyen en el riesgo de dengue en la región Arizona-Sonora (in Spanish). Meeting with Sonoran Health Dept. in Santa Ana, Sonora.
• Walker, K. R., Ernst, K. C., Reyes-Castro, P., Castro, L., & Diaz-Cervantes, R. (2015, August). Factores que influyen en el riesgo de dengue en la región Arizona-Sonora. Reunion sobre el control de enfermedades transmitido por insectos. Ciudad Obregon, Sonora, Mexico: Instituto Technologica de Sonor.
• Ernst, K. C., Hayden, M. H., Walker, K. R., Castro, L., Caravantes, R., Castro-Reyes, P., Monaghan, A., Haenchen, S., & Riehle, M. A. (2014, July). Aedes aegypti indices in the Arizona-Sonora border region. Arizona Department of Health Services Infectious Disease Epidemiology Conference. Phoenix, AZ.
• Ernst, K. C., Hayden, M. H., Walker, K. R., Castro, L., Caravantes, R., Castro-Reyes, P., Monaghan, A., Haenchen, S., & Riehle, M. A. (2014, November). Diferencias en el riesgo del dengue a través del norte de México. El Colegio de Sonora Prevención de riesgos para la salud de las poblaciones vulnerables. Hermosillo, SN.
• Ernst, K. C., Hayden, M., Riehle, M. A., & Walker, K. R. (2014, August). Differential Emergence of Dengue in the Arizona-Sonora Desert Region: Understanding the Role of Social and Environmental Factors.”. International Society for Environmental Epidemiology.
• Walker, K. R. (2014, April). Who Cares About Fruit flies? Communicating Scientific Models. Annual Meeting - Pacific Branch of the Entomological Society of America. Tucson, AZ.
• Walker, K. R., & Ernst, K. C. (2014, Fall). Factores que influyen en el riesgo de dengue en la región Arizona-Sonora. Training event for nurses & hospital staff - Hospital General Nogales. Nogales, Sonora, Mexico: Hospital General Nogales.

Poster Presentations

• Ellsworth, P. C., Teegerstrom, T., Ernst, K. C., Walker, K. R., Brophy, M., Reese, S., Dorame-Avalos, A., Nair, S., Fournier, A. J., Gouge, D. H., & Li, S. (2020, October 6-8). Honoring and Empowering Tribal Nations and Indigenous Peoples Through IPM Education and Emergency Preparedness. 2020 Arizona Cooperative Extension Virtual Conference. October 6-8, 2020.
• Walker, K. R., Carriere, Y., Gouge, D. H., Ernst, K. C., Joy, T., & Riehle, M. A. (2020, November). How old is that mosquito? Age grading Aedes aegypti in the desert Southwest.. ESA National Meeting. Virtual.
• Fournier, A. J., Fournier, A. J., Fournier, A. J., Ellsworth, P. C., Ellsworth, P. C., Ellsworth, P. C., Teegerstrom, T., Teegerstrom, T., Teegerstrom, T., Rivadeneira, P., Rivadeneira, P., Rivadeneira, P., Ernst, K. C., Ernst, K. C., Ernst, K. C., Walker, K. R., Walker, K. R., Walker, K. R., Reese, S. K., , Reese, S. K., et al. (2019, August). Public Health IPM Education in American Indian Communities. University of Arizona Cooperative Extension Annual In-Service Training. Tucson, Arizona.
• Fournier, A. J., Fournier, A. J., Fournier, A. J., Ellsworth, P. C., Ellsworth, P. C., Ellsworth, P. C., Teegerstrom, T., Teegerstrom, T., Teegerstrom, T., Rivadeneira, P., Rivadeneira, P., Rivadeneira, P., Rivadeneira, P., Rivadeneira, P., Rivadeneira, P., Ernst, K. C., Ernst, K. C., Ernst, K. C., Walker, K. R., , Walker, K. R., et al. (2019, 08-06-2019). Public Health IPM Education in American Indian Communities. 2019 Arizona Cooperative Extension Conference.
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  8/6/19. Li, S., Gouge, D.H., Nair, S., Dorame-Avalos, A., Reese, S.K., Brophy, M., Walker, K.C., Ernst, K.C., Rivadeneira, P., Teegerstrom, T., Ellsworth, P.C. and Fournier, A.J. (presented the poster). 2019. Public Health IPM Education in American Indian Communities. Poster presentation. 2019 Arizona Cooperative Extension Conference. Westin La Paloma Resort, 3800 E. Sunrise Dr., Tucson, AZ 85718. August 6-7, 2019.
• Walker, K. R., Gouge, D. H., Brophy, M., & Arnbrister, J. (2019, September). Pilot Testing of In2Care® Traps in Urban Desert Landscape. SOVE 49th Annual Conference. San Juan, Puerto Rico: Society for Vector Ecology.
• Ernst, K. C., Gouge, D. H., Riehle, M. A., & Walker, K. R. (2018, October). Impacts of ULV adulticiding on the vectorial capacity of the Zika Vector. Society of Vector Ecology. Yosemite, California.
• Joy, T., Walker, K. R., Ernst, K. C., & Riehle, M. A. (2018, October). Age grading individual field collected Aedes aeg ypti mosquitoes: qPCR versus near - infrared spectrophotometry (NIRS). Society of Vector Ecology. Yosemite, California.
• Walker, K. R., Ernst, K. C., Joy, T., Reyes-Castro, P., Carriere, Y., Castro, L., Diaz-Cervantes, R., Gameros, M., Hayden, M., Monaghan, A., Haenchen, S., Guttierez-Jeffrey, E., & Riehle, M. A. (2015, September). Exploring differential emergence of dengue in two cities with established Aedes aegypti populations: A case study in Sonora, Mexico. 2015 Annual Meeting of the Society for Vector Ecology. Albuquerque, NM.

Creative Productions

• Walker, K. R., & Riehle, M. A. (2017. Why mosquitoes love us, but we don't love them. Live-stream video. University of Arizona: FIeldTrip Zoom.
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  Live-stream educational presentations to elementary schools. Estimated 300 classes participated.

Creative Performances

• Walker, K. R. (2012. Insect Festival - interview. Arizona Illustrated television program. University of ARizona: Arizona Public Media.
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  Arizona Illustrated program. Graduate student Jason Schaller and I provided a short presentation about insects and discussed the upcoming Insect Festival.
• Walker, K. R. (2011. Electronic Field Trip. National Park Service - Saguaro National Park Bio-Blitz. Saguaro National Park - West: National Park Service.
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  I served as a co-host with a National Park Service Ranger for a live, on-line broadcast of the BioBlitz. My role was to answer questions about desert natural history that young students emailed in during the broadcast.

Others

• Ramberg, F., Sumner, C., Brophy, M., Walker, K. R., Nair, S., Li, S., & Gouge, D. H. (2020, June). Mosquitoes (IPM Brochure Trifold). University of Arizona Cooperative Extension.
• Walker, K. R., Nair, S., Stefanakos, E., Ernst, K. C., Huijben, S., Ruberto, I., Li, S., Paaijmans, K., Sumner, C., & Gouge, D. H. (2021, June). Department of Health and Human Services: HHS-OASH-2021-0012-0001 - Developing the National Public Health Strategy for the Prevention and Control of Vector-Borne Diseases in Humans. Comment Tracking Number: kpi-n16l-jv9p.. Department of Health and Human Services Request for Information.
• Andrade Sanchez, P., Walker, K. R., Brophy, M., Nair, S., Li, S., & Gouge, D. H. (2020, July). Mosquitos (Mosquitoes in Spanish - Quick Read Trifold). University of Arizona Cooperative Extension.
• Andrade Sanchez, P., Walker, K. R., Brophy, M., Nair, S., Li, S., & Gouge, D. H. (2020, July). Mosquitos (Mosquitoes in Spanish) AZ1873S Trifold Quick Read. University of Arizona Cooperative Extension. https://extension.arizona.edu/sites/extension.arizona.edu/files/pubs/az1873S-2021.pdf
• Andrade Sanchez, P., Walker, K. R., Brophy, M., Nair, S., Li, S., & Gouge, D. H. (2020, July). Mosquitos (Mosquitoes in Spanish). Trifold Quick Read. University of Arizona Cooperative Extension.
• Andrade Sanchez, P., Walker, K. R., Brophy, M., Nair, S., Li, S., & Gouge, D. H. (2020, October). Mosquitoes (English Trifold Quick Read). University of Arizona Cooperative Extension, AZ1873. https://extension.arizona.edu/sites/extension.arizona.edu/files/pubs/az1873-2021.pdf
• Andrade Sanchez, P., Walker, K. R., Brophy, M., Nair, S., Li, S., & Gouge, D. H. (2020, October). Mosquitoes (English Trifold Quick Read). University of Arizona Cooperative Extension, az1873. https://extension.arizona.edu/sites/extension.arizona.edu/files/pubs/az1873-2021.pdf
• Andrade Sanchez, P., Walker, K. R., Brophy, M., Nair, S., Li, S., & Gouge, D. H. (2020, October). Mosquitoes (English Trifold Quick Read). University of Arizona Cooperative Extension.
• Andrade Sanchez, P., Walker, K. R., Brophy, M., Nair, S., Li, S., & Gouge, D. H. (2021, October). Mosquitoes AZ 1873 (English Trifold Quick Read). University of Arizona Cooperative Extension. https://extension.arizona.edu/sites/extension.arizona.edu/files/pubs/az1873-2021.pdf
• Andrade Sanchez, P., Walker, K. R., Brophy, M., Nair, S., Li, S., & Gouge, D. H. (2021, September). Mosquitos (Mosquitoes in Spanish). Trifold Quick Read. University of Arizona Cooperative Extension, AZ1873S. https://extension.arizona.edu/sites/extension.arizona.edu/files/pubs/az1873S-2021.pdf
• Andrade Sanchez, P., Walker, K. R., Li, S., Gouge, D. H., & Nair, S. (2020, October). Mosquito and Tick Repellents (English Quick Read Trifold). University of Arizona Cooperative Extension.
• Andrade Sanchez, P., Walker, K. R., Li, S., Gouge, D. H., & Nair, S. (2020, September). Repelentes de mosquitos y garrapatas (Mosquito and Tick Repellents in Spanish Quick Read Trifold).. University of Arizona Cooperative Extension.
• Andrade Sanchez, P., Walker, K. R., Nair, S., Brophy, M., Gouge, D. H., & Li, S. (2020, December). Brown dog ticks and Rocky Mountain spotted fever (English Quick Read Trifold). University of Arizona Cooperative Extension.
• Andrade Sanchez, P., Walker, K. R., Nair, S., Brophy, M., Gouge, D. H., & Li, S. (2020, September). Garrapatas marrones del perro y fiebre maculosa de las Montañas Rocosas (BDT & RMSF in Spanish Quick Read Trifold). University of Arizona Cooperative Extension.
• Andrade Sanchez, P., Walker, K. R., Nair, S., Brophy, M., Gouge, D. H., & Li, S. (2021, July). Brown dog ticks and Rocky Mountain spotted fever (English Quick Read Trifold). University of Arizona Cooperative Extension, AZ1935. https://extension.arizona.edu/sites/extension.arizona.edu/files/pubs/az1935-2021.pdf
• Andrade Sanchez, P., Walker, K. R., Nair, S., Brophy, M., Gouge, D. H., & Li, S. (2021, October). Garrapatas marrones del perro y fiebre maculosa de las Montañas Rocosas (BDT & RMSF in Spanish Quick Read Trifold). University of Arizona Cooperative Extension, AZ1935S. https://extension.arizona.edu/sites/extension.arizona.edu/files/pubs/az1935S-2021.pdf
• Brophy, M., Walker, K. R., Nair, S., Gouge, D. H., & Li, S. (2021, October). Brown Dog Ticks. University of Arizona Cooperative Extension. Brochure. AZ1871. https://extension.arizona.edu/sites/extension.arizona.edu/files/pubs/az1871-2021.pdf
• Brophy, M., Walker, K. R., Nair, S., Gouge, D. H., & Li, S. (2021, October). Brown Dog Ticks. University of Arizona Cooperative Extension. Brochure. AZ1871.. https://extension.arizona.edu/sites/extension.arizona.edu/files/pubs/az1871-2021.pdf
• Ramberg, F., Sumner, C., Brophy, M., Walker, K. R., Nair, S., Li, S., & Gouge, D. H. (2020, June). Mosquitoes (technical trifold). University of Arizona Cooperative Extension.
• Ramberg, F., Sumner, C., Brophy, M., Walker, K. R., Nair, S., Li, S., & Gouge, D. H. (2021, April). Mosquitoes and Disease Concerns (technical trifold). University of Arizona Cooperative Extension, AZ1912. https://extension.arizona.edu/sites/extension.arizona.edu/files/pubs/az1912-2021.pdf
• Ramberg, F., Sumner, C., Walker, K. R., Brophy, M., Nair, S., Li, S., & Gouge, D. H. (2021, June). Mosquitoes and Disease Concerns AZ1912 (technical trifold). University of Arizona Cooperative Extension. https://extension.arizona.edu/sites/extension.arizona.edu/files/pubs/az1912-2021.pdf
• Walker, K. R., Li, S., Gouge, D. H., & Nair, S. (2020, August). Mosquito and Tick Repellents (IPM Brochure Trifold). University of Arizona Cooperative Extension.
• Walker, K. R., Li, S., Gouge, D. H., & Nair, S. (2021, April). Mosquito and Tick Repellents. University of Arizona Cooperative Extension, AZ1913. https://extension.arizona.edu/sites/extension.arizona.edu/files/pubs/az1913-2021.pdf
• Bibbs, C. S., Walker, K. R., Nair, S., Li, S., & Gouge, D. H. (2018, Jan). Mosquito and Tick Repellents. University of Arizona Cooperative Extension. https://cals.arizona.edu/apmc/docs/Mosquito-and-Tick-Repellents.pdf
• Fournier, A. J., Walker, K. R., Nair, S., Gouge, D. H., & Li, S. (2020, September). What you should know about mosquito and tick repellents (IPM Short). Arizona Pest Management Center Public Health Pest Website. https://acis.cals.arizona.edu/docs/default-source/community-ipm-documents/public-health-ipm/border-2020-outputs/2020-repellents-ipm-short.pdf
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  Extension IPM Short (Revision)
• Fournier, A. J., Walker, K. R., Nair, S., Gouge, D. H., & Li, S. (2020, September). What you should know about mosquito and tick repellents. https://acis.cals.arizona.edu/docs/default-source/community-ipm-documents/public-health-ipm/border-2020-outputs/2020-repellents-ipm-short.pdf
  More info

  Extension IPM Short (Revision)
• Walker, K. R., Nair, S., Gouge, D. H., Brophy, M., & Li, S. (2020, September). Brown dog ticks and repellents. Community IPM Newsletter. https://acis.cals.arizona.edu/community-ipm/home-and-school-ipm-newsletters/ipm-newsletter-view/ipm-newsletters/2020/09/03/brown-dog-ticks-and-repellents
• Casal, M., Ortiz Encinas, V., Walker, K. R., Yaglom, H., Gouge, D. H., & Brophy, M. (2019, December). La garrapata café del perro y la epidemia de rickettsiosis en Arizona y en el noroeste de México. University of Arizona Cooperative Extension.
• Fournier, A. J., Walker, K. R., Gouge, D. H., & Li, S. (2019, January). Asian Longhorned Tick, an Invasive Tick in the United States. University of Arizona Cooperative Extension.
• Fournier, A. J., Walker, K. R., Gouge, D. H., & Li, S. (2019, January). Longhorned Tick, a New Invasive Tick in the United States.. University of Arizona Cooperative Extension.
• Ramberg, F., Olson, C., Nair, S., Sumner, C., Walker, K. R., Li, S., & Gouge, D. H. (2019, September). Mosquitoes: Biology and Integrated Mosquito Management AZ1706. University of Arizona Cooperative Extension. http://extension.arizona.edu/pubs/az1706-2019.pdf
• Ramberg, F., Olson, C., Nair, S., Sumner, C., Walker, K. R., Li, S., & Gouge, D. H. (2019, September). Mosquitoes: Biology and Integrated Mosquito Management.. http://extension.arizona.edu/pubs/az1706-2019.pdf
• Andrade Sanchez, P., Andrade Sanchez, P., Fournier, A. J., Fournier, A. J., Walker, K. R., Walker, K. R., Nair, S., Nair, S., Gouge, D. H., Gouge, D. H., Li, S., Li, S., Andrade Sanchez, P., Fournier, A. J., Walker, K. R., Nair, S., Gouge, D. H., & Li, S. (2018, Septiembre). Lo que debe saber sobre los repelentes de mosquitos y garrapatas. Extensión Cooperativa de la Universidad de Arizona, corto de MIP. https://cals.arizona.edu/apmc/docs/Repellents-IPMShort-Spanish.pdf
• Bibbs, C. S., Bibbs, C. S., Walker, K. R., Walker, K. R., Nair, S., Nair, S., Li, S., Li, S., Gouge, D. H., & Gouge, D. H. (2018, Jan). Mosquito and Tick Repellents. University of Arizona Cooperative Extension AZ. https://cals.arizona.edu/apmc/docs/Mosquito-and-Tick-Repellents.pdf
• Casal, M., Ortiz Encinas, V., Walker, K. R., Yaglom, H., Gouge, D. H., & Brophy, M. (2018, December). La garrapata café del perro y la epidemia de rickettsiosis en Arizona y en el noroeste de México. University of Arizona Cooperative Extension.
• Fournier, A. J., Fournier, A. J., Walker, K. R., Walker, K. R., Gouge, D. H., Gouge, D. H., Li, S., & Li, S. (2018, August). Longhorned Tick, a New Invasive Tick in the United States.. University of Arizona Cooperative Extension IPM Short. http://cals.arizona.edu/apmc/docs/longhorned-tick.pdf
• Fournier, A. J., Fournier, A. J., Walker, K. R., Walker, K. R., Nair, S., Nair, S., Gouge, D. H., Gouge, D. H., Li, S., & Li, S. (2018, September). What you should know about mosquito and tick repellents.. University of Arizona Cooperative Extension IPM Short. https://cals.arizona.edu/apmc/docs/Repellents-IPMShort.pdf
• Veronica, E., Walker, K. R., Mariana, C., Gouge, D. H., Maureen, B., Hayley, Y., Hayley, Y., Maureen, B., Mariana, C., Gouge, D. H., Veronica, O., & Walker, K. R. (2018, March). The Brown Dog Tick and Epidemic Rocky Mountain Spotted Fever in Arizona, United States and Sonora, Mexico. University of Arizona Cooperative Extension AZ.
• Gouge, D. H., Li, S., Walker, K. R., Sumner, C., Nair, S., Bibbs, C., & Hagler, J. (2017, Spring). Disease Causing Viruses Vectored by Mosquitoes.. University of Arizona Cooperative Extension.
• Hagler, J., Bibbs, C., Nair, S., Sumner, C., Walker, K. R., Li, S., & Gouge, D. H. (2017, Spring). Disease Causing Viruses Vectored by Mosquitoes.. University of Arizona Cooperative Extension AZ1744.
• Beal, B., & Walker, K. R. (2016, Summer). Giant Swallowtail.. Backyards and Beyond: Rural Living in Arizona. University of Arizona Cooperative Extension..
• Gouge, D. H., Li, S., Walker, K. R., Sumner, C., Nair, S., & Olson, C. (2016, June). Mosquitoes: Biology and Integrated Mosquito Management. University of Arizona Cooperative Extension. https://extension.arizona.edu/sites/extension.arizona.edu/files/pubs/az1706-2016.pdf
• Gouge, D. H., Li, S., Walker, K. R., Sumner, C., Nair, S., & Olson, C. A. (2016, Winter). Mosquitoes: Biology and Integrated Pest Management.. University of Arizona Cooperative Extension AZ1706, pp. 12.. http://extension.arizona.edu/sites/extension.arizona.edu/files/pubs/az1706-2016.pdf
• Li, S., Gouge, D. H., Walker, K. R., Fournier, A. J., Nair, S., Wierda, M. R., Hurley, J., Li, S., Gouge, D. H., Walker, K. R., Fournier, A. J., Nair, S., Wierda, M. R., & Hurley, J. (2016, February). The Zika Virus. University of Arizona, Arizona Pest Management Center. https://cals.arizona.edu/apmc/docs/Zika-virus.pdf
• Li, S., Li, S., Gouge, D. H., Gouge, D. H., Walker, K. R., Walker, K. R., Fournier, A. J., Fournier, A. J., Nair, S., Nair, S., Wierda, M. R., Wierda, M. R., Hurley, J., & Hurley, J. (2016, May). The Zika Virus. APMC website. http://cals.arizona.edu/apmc/docs/Zika-virus.pdf