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ARS Home » Southeast Area » Gainesville, Florida » Center for Medical, Agricultural and Veterinary Entomology » Mosquito and Fly Research » Research » Research Project #423667


Location: Mosquito and Fly Research

2013 Annual Report

1a. Objectives (from AD-416):
1. Disseminate and obtain feedback about surveillance and control strategies developed for area-wide control of Aedes albopictus. 2. Disseminate and obtain feedback from recent economic analyses and provide a user friendly costing tool for vector control managers developed by the area-wide project. 3. Complete transfer of novel entomological and economic strategies to end-users.

1b. Approach (from AD-416):
Will extend the results and experiences derived from field trials and evaluations for the surveillance and control of the Asian tiger mosquito in Mercer and Monmouth Counties (New Jersey) to other areas where this mosquito is distributed and problematic. This will include utilization of Standard Operating Procedures (SOPs) developed and evaluated over the last five years. In addition, emerging information about insecticide resistance in this species and its patterns of introduction into the continental United States will be incorporated into control strategies. A unique aspect of this project will be the provision of a user friendly costing tool for vector control managers that will enable them to collect information about this increasingly important issue for mosquito control program managers. Technology transfer will be accomplished by presentations at a variety of local, state, national and international meetings; publications in peer-reviewed journals; and establishment of a unique website at the Center for Vector Biology at Rutgers University that will be dedicated to the latest information on the biology and management of the Asian tiger mosquito. These communications will involve a multidisciplinary approach between local, state, federal, international and private interests; whose participants will be involved in the program throughout its development and expansion.

3. Progress Report:
FY2012 included activities being developed in several locations in New Jersey and Florida. Fieldwork (surveillance and control) was initiated and terminated as per established protocols and in some cases such as in Florida, progressed throughout the “winter”. The main objectives for 2012 and 2013 were to (1) summarize, analyze and publish results as well as develop detailed Standard Operating Procedures to be made available to other mosquito control programs; (2) test of Standard Operational Procedures by collaborating mosquito control programs in NJ and other states besides NJ; (3) understand the mechanisms underlying the observed marked differences in success between urban and suburban sites by performing extensive comparative analysis of larval development in cryptic habitats, developing “common garden” experiments, and using newly developed molecular tools; (4) finish the extensive comparative analysis of insecticide resistance in U.S. populations of Aedes albopictus. Overall, this 5-year project revealed that populations of Aedes albopictus, the Asian tiger mosquito, in the U.S. are highly associated with human dwellings and use humans as the predominant source of blood. As a result they have a considerable impact on quality of life, as measured by our economist colleagues at Brandeis University. The willingness to pay (WTP) survey was conducted in 2010 for 400 randomly selected households in the six study sites. The cooperation rate was 67.5%. The majority (54.6%) of respondents considered mosquitoes a problem. Mosquitoes prevented 59.5% of respondents from enjoying their outdoor activities to some extent. During a summer week, 51% of respondents reported being bitten on average 7.1 bites per week, 77.7% were bitten outdoors compared to 22.3% indoors. Of those bitten, 49.6% used existing products at home to treat their bites, 34.7% bought new products, and 4.2% saw a health care provider. The average amount paid out-of-pocket per person on treatment over the summer for mosquito bite products was $9.10 and $9.71 on medical providers, while insurance paid on average $13.14. Indeed, we found that childhood activity outdoors increases significantly in areas where our proposed control measures have been implemented. Our work also revealed that populations of Ae. albopictus are locally adapted and highly dependent on local conditions of heat and humidity. As a result, the guidelines we developed for control of this pest need to be fine-tuned locally with the aid of a degree-day model and tandem broadcast applications of larvicides and adulticides. As of this time, U.S. populations are susceptible to most classes of insecticides although our analysis revealed resistance to both DDT and malathion (an organochlorine and organophosphate, respectively). We found also that education, especially active engagement, is a critical tool towards recruiting local residents in performing source reduction as well as allowing access of mosquito control personnel to private residences (where most of the immature development occurs).

4. Accomplishments
1. Demonstrated that area-wide single and tandem applications of adulticides and larvicides have a significant impact on Aedes albopictus (ATM) populations. From 2009 to 2011, researchers optimized area-wide applications of Bacillus thuringiensis var. israelensis (Bti) (larvicide) and DUET (adulticide) and achieved consistent results. In 2011, it was confirmed that DUET had a significant but ephemeral impact on adult populations of Ae. albopictus and that tandem applications with larvicides extended the control. In 2012, researchers implemented successive applications of Bti and to fully test the impact of larvicide applications, chose not to apply adulticides in tandem. Area-wide applications of full rate Bti with a Buffalo Turbine machine were made for two successive weeks. In both cases, bioassays demonstrated >95% efficacy (no difference between the front, middle, and back of residential parcels) with significant decreases in the number of adult ATM.

2. Prepared Standard Operational Procedures (SOP) for control of ATM. These step-by-step files detail all the strategies that were successfully implemented: (1) Aedes albopictus BG-Sentinel trapping recommendations; (2) truck-mounted larviciding with Methoprene; (3) truck mounted larviciding with Bti; (4) bioassays for Methoprene; (5) bioassays for Bti; (6) adulticide (DUET) application SOP; (7) ovitrap surveillance; and (8) rapid assay for identification of blood meals in Ae. albopictus. They have been made available to mosquito control programs with ATM infestations. To date, distribution and discussion of these protocols have been made with over 15 separate mosquito control programs.

3. Created a standard susceptible colony of Asian Tiger Mosquito for insecticide resistance and characterized eight field populations of Ae. albopictus from NJ, PA, and FL. Researchers examined all classes of insecticides (organochlorides, carbamates, organophosphates, and IGRs [insect growth regulators]). Specifically, this colony was tested for susceptibility to a wide spectrum of insecticides (e.g., Bti, Spinosad, Temephos, Propoxur, Methoprene, Pyriproxifen, DDT, Malathion, Deltamethrin, Prallethrin, and Phenothrin). Specimens were provided to colleagues for informed comparisons of insecticide resistance (IR) across laboratories and ATM populations. Findings showed that overall U.S. populations are susceptible but found significant resistance to DDT in two FL populations and resistance is suspected in a NJ population. We also found moderate levels of resistance to Malathion, an organophosphate, in FL and NJ and reduced susceptibility to the IGRs Pyriproxifen and Methoprene. Detailed biochemical assays revealed a significant up-regulation of glutathione S-transferases (GSTs) in DDT-resistant populations and ß-esterases were up-regulated in populations with incipient resistance to Malathion. A previously unknown amino acid polymorphism in domain III of the sodium channel target was identified.

4. Evidence of significant differentiation between U.S. populations of Aedes albopictus. Analysis of the population genetics of ATM across the U.S. has demonstrated unexpected patterns of differentiation often between relatively close populations (< 50 miles apart) that agree with findings that like other Aedes species, ATM is a weak flyer. In addition, common garden behavioral tests have identified differences between urban and suburban populations of Ae. albopictus. Importantly, these findings shed light on crucial differences observed between urban and suburban populations and combined with the results from insecticide resistance tests they indicate both multiple introductions of Ae. albopictus into the U.S. as well as post-introduction differentiation driven locally by temperature, humidity and availability of oviposition sites. These results are in line with recent research in Anopheles populations and place the project in the forefront of research in the ecology, evolution, and control of disease vectors.

Review Publications
Fonseca, D., Unlu, I., Crepeau, T., Farajollahi, A., Healy, S., Bartlett-Healy, K., Strickman, D.A., Gaugler, R., Kline, D.L., Clark, G.G. 2013. Area-wide management of Aedes albopictus: II. Gauging the efficacy of traditional integrated pest control measures against urban container mosquitoes. Pest Management Science. 67:965–974.

Halasa, Y.A., Shepard, D.S., Wittenberg, E., Fonseca, D.M., Farajollahi, A., Healy, S., Gaugler, R., Strickman, D.A., Clark, G.G. 2012. Willingness-to-pay for an area-wide integrated Pest Managment Program to control the Asian Tiger Mosquito in New Jersey. Journal of the American Mosquito Control Association. 28(3):225-236.