Protecting Military Personnelby Controlling Host-Seeking Arthropods

Brian QuinnUSDA/ARS/CMAVE/MFRU

Gainesville, Florida

Topics

1) Screening endemic plants for toxicant and repellent compounds

2) Barrier spraying with cyfluthrin

3) Evaluation of thermal foggers

Screening Endemic Plants for New Toxicants and Repellents

1) Plants were extracted with three different solvents (hexane, dichloromethane, and methanol) to collect a wide range of organic compounds

2) Extracts were concentrated and analyzed by GC/MS to determine chemical components

Screening Endemic Plants (cont.)

3) List of candidate plants prepared by examining older literature on plant use by settlers and Native Americans as well as current literature

4) Certain plant families from southeastern US were highlighted after multiple species within the families were found to have bioactive compounds

Bioassays for Plant Extracts

• Extracts are evaluated for toxicity using the WHO topical assay

• Repellency of the same extract is evaluated using the cloth patch test

Etonia rosemary (Conradina etonia)

Chromatogram of Etonia RosemaryRT: 0.00 - 46.53

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14.99

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18.92

23.60 25.1217.8411.458.957.81 26.83

29.38 31.88 45.6540.03

NL:3.12E8TIC F: MS BQ-111506-B

x5 x5

Camphor

Caryophyllene oxide

Eucalyptol

Mass Spectrum of CamphorBQ-111506-B #1708 RT: 14.97 AV: 1 SB: 2 14.79 , 15.17 NL: 2.50E7T: + c Full ms [ 35.00-550.00]

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94.94

80.97 107.96 152.02

68.95 109.01

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154.02 230.97 344.13267.41 370.99 441.09 530.93

Summary – Native Plant Extraction

• To date, 33 plant extracts have been prepared and these have been evaluated for bioactivity against Aedes aegypti mosquitoes

• Individual chemical components identified by GC/MS from these extracts are currently being evaluated for repellency and toxicity to mosquitoes

Summary (cont.)

• Military relevance – New repellents and insecticides needed to combat vector-borne diseases; natural products are often more acceptable to the public, including deployed military personnel.

• Future work – Evaluate additional chemical components with bioactivity against biting insects.

Barrier Spraying

• Adulticide technique for controlling biting insects in a designated area

• Utilization could provide effective and lasting control while using much less product than in space sprays

• Different leaf integuments may influence residual pesticide concentrations and efficacy

Barrier Spraying Methodology

• Backpack sprayer used to coat plants with Tempo (a.i. cyfluthrin)

• Samples taken weekly for bioassays and chemical analysis

• Bioassay modeled after the WHO tarsal contact method

• Pesticide residue testing- soon to be completed

Barrier Spraying Methodology

• Plants used in this study:

Southern Magnolia (Magnolia grandiflora)

Salt Cordgrass (Spartina bakeri)

American Beautyberry (Callicarpa americana)

Southern Magnolia

Salt Cordgrass

American Beautyberry

Mixing the Cyfluthrin Formulation

Plants Before Application

Low Volume Application of Tempo on Cordgrass

Plants after Application

Summary – Barrier Spraying

• Military relevance – When applied properly, barrier sprays have the potential to effectively protect encampments from biting insects at a fraction of the cost of space spraying.

• Future work – Continue collaborative studies with NECE to evaluate additional application equipment and adulticides under different climatic conditions.

Thermal Fogger Study

• Four major equipment manufacturers, industry colleagues, military personnel, and ARS scientists collaborated to study droplet size and pesticide degradation at NECE from January 22-24, 2007.

• Twelve thermal foggers were evaluated using the following five formulations: Anvil 10+10 (d-phenothrin), Fyfanon (malathion), Kontrol 30-30 (permethrin), Aqua-Reslin (permethrin), and Aqualuer (permethrin).

Thermal Fogger Evaluation

• Analyzed prepared formulations

• Collected fog and analyzed the insecticide generated by the different thermal foggers to determine the pesticide concentrations

• Compared initial formulation with output.

Thermal Fogger Evaluation

• Droplet size evaluation performed by Clint Hoffmann (APMRU/ARS) using a laser array apparatus

• Teflon-coated slide method used by NECE personnel to measure droplet size

• AIMS (hot wire) method operated by Todd Gwinn of ADAPCO

Collecting Fog Samples from Dyna Fog

Collecting Fog Samples from London Fog

Beaker with Pesticide Fog

Transferring Sample from Beaker to Vials

Summary – Thermal Foggers

• Pesticide degradation in thermal foggers has been poorly studied in the past. These data will be used to provide guidance for assigning future national stock numbers (NSN) to thermal foggers for use by military personnel.

• Military relevance – Thermal foggers are powerful tools for effectively applying adulticides over a large area. Currently, there are only three thermal foggers with an NSN.

Acknowledgements

• DWFP funding• CMAVE staff• NECE staff – Todd Walker and Vincent Smith• Thermal fogger manufacturers• Todd Gwinn – ADAPCO• Clint Hoffmann – APMRU/ARS