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Raina A.,U.S. Department of Agriculture | Bedoukian R.,Bedoukian Research Inc. | Florane C.,U.S. Department of Agriculture | Lax A.,U.S. Department of Agriculture
Journal of Economic Entomology | Year: 2012

Twenty-nine natural products and their derivatives were tested for both contact and vapor toxicity against the Formosan subterranean termite, Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae). Five natural products at 0.5% (wt:wt) in petri dish contact assay caused 100% mortality within 3 d. In vapor form, only three chemicals (styrallyl alcohol, 2-phenyl-2-propanol, and l-carvone) at 0.25 l/liter air caused >90% mortality in 3 d when tested on exposed termites. However, when termites were shielded by wood and soil, only one chemical, tetrahydrocarvone at 25 l/liter air caused 100% mortality in 2 d. Preliminary test with termites in carton nests, exposed to tetrahydrocarvone vapor in desiccators, resulted in an average of 98.6% mortality in 7 d. With further development in the method of delivery, this chemical may be very useful in fumigating confined areas of termite infestation.

Carroll J.F.,Biocontrol | Kramer M.,U.S. Department of Agriculture | Bedoukian R.H.,Bedoukian Research Inc.
Journal of Medical Entomology | Year: 2014

Behavioral bioassays remain a standard tool in the discovery, development, and registration of arthropod repellents. Tick repellent bioassays are generally uncomplicated, but their results can be affected by basic variables (e.g., dimensions of testing materials, substrate, timing, temperature) of the assay. Using lone star tick, Amblyomma americanum (L.), nymphs in climbing bioassays, we tested for the effects of substrate, solvent, and drying time on tick responses. In dose-response tests, the widely used repellents N,N-diethyl-3-methyl benzamide (deet) and 1-methylpropyl-2-(hydroxyethyl)-l- piperidinecarboxylate (picaridin) were applied to filter paper strips and challenged by ticks at 10, 20, 30, 40, and 120 min after application. At 10-min drying time, repellency at the intermediate concentration 500 nmol repellent/cm2 filter paper was significantly lower for ethanol solutions of deet and picaridin (0 and 10% ticks repelled, respectively) than for solutions of deet and picaridin in acetone (96.7 and 76.7% ticks repelled, respectively). Repellency was greatest for both the acetone and ethanol solutions of deet and picaridin when challenged 120 min after application, and at shorter drying times at the highest concentration tested (2,000 nmol compound/cm2). The repellency of picaridin relative to deet differed at some combinations of solvent and drying time but not others. In dose-response tests using different paper substrates and a drying time of 10 min, both ethanol and acetone solutions of deet differed in repellency, depending on both the paper substrate and the solvent. However, there were no differences in repellency between ethanol and acetone solutions of deet applied to nylon organdy in an in vitro and in an in vivo (fingertip) bioassay. When deet in solution with various proportions of ethanol:water was applied at 2,000 nmol deet/cm2 filter paper, the proportion of ticks repelled decreased as the proportion of water in the test solutions increased. Somewhat similar results were seen for solutions of deet in an acetone solvent. Water absorbed from the atmosphere may affect the efficacy of repellents in solution with anhydrous ethanol. Overall, results obtained from bioassays that differ in seemingly minor ways can be surprisingly different, diminishing the value of comparing studies that used similar, but not identical, methods. Nylon organdy or another similar thin cloth may be preferable to filter papers and copier paper for minimizing solvent-related differences. When a paper substrate is used, acetone may be the more suitable solvent if the solubility of the test compound and other factors allow. © 2014 Entomological Society of America.

Krueger A.C.,Abbvie Inc. | Randolph J.T.,Abbvie Inc. | Degoey D.A.,Abbvie Inc. | Donner P.L.,Abbvie Inc. | And 17 more authors.
Bioorganic and Medicinal Chemistry Letters | Year: 2013

The synthesis and structure-activity relationships of a novel aryl uracil series which contains a fused 5,6-bicyclic ring unit for HCV NS5B inhibition is described. Several analogs display replicon cell culture potencies in the low nanomolar range along with excellent rat pharmacokinetic values. © 2013 Elsevier Ltd. All rights reserved.

Weldon P.J.,Smithsonian Conservation Biology Institute | Carroll J.F.,Biocontrol | Kramer M.,U.S. Department of Agriculture | Bedoukian R.H.,Bedoukian Research Inc. | And 2 more authors.
Journal of Chemical Ecology | Year: 2011

Some birds and mammals roll on or wipe themselves with the fruits or leaves of Citrus spp. or other Rutaceae. These anointing behaviors, as with anointing in general, are thought to function in the topical acquisition of chemicals that deter consumers, including hematophagous arthropods. We measured avoidance and other responses by nymphal lone star ticks (Amblyomma americanum) and adult female yellow fever mosquitoes (Aedes aegypti) to lemon peel exudate and to 24 volatile monoterpenes (racemates and isomers), including hydrocarbons, alcohols, aldehydes, acetates, ketones, and oxides, present in citrus fruits and leaves in order to examine their potential as arthropod deterrents. Ticks allowed to crawl up vertically suspended paper strips onto a chemically treated zone avoided the peel exudate and geraniol, citronellol, citral, carveol, geranyl acetate, α-terpineol, citronellyl acetate, and carvone. Ticks confined in chemically treated paper packets subsequently were impaired in climbing and other behaviors following exposure to the peel exudate and, of the compounds tested, most impaired to carveol. Mosquitoes confined in chambers with chemically treated feeding membranes landed and fed less, and flew more, when exposed to the peel exudate than to controls, and when exposed to aldehydes, oxides, or alcohols versus most hydrocarbons or controls. However, attraction by mosquitoes in an olfactometer was not inhibited by either lemon peel exudate or most of the compounds we tested. Our results support the notion that anointing by vertebrates with citrus-derived chemicals deters ticks. We suggest that some topically applied compounds are converted into more potent arthropod deterrents when oxidized on the integument of anointed animals. © 2011 Springer Science+Business Media, LLC (outside the USA).

Cloonan K.,University of California at Davis | Bedoukian R.H.,Bedoukian Research Inc. | Leal W.,University of California at Davis
PLoS ONE | Year: 2013

A three-step, quasi-double-bind approach was used as a proof-of-concept study to screen twenty compounds for their ability to reduce oviposition of gravid female navel orangeworm(NOW), Ameylois transitella (Lepidoptera: Pyralidae). First, the panel of compounds, whose identity was unknown to the experimenters, was tested by electroantennogram (EAG) using antennae of two-day old gravid females as the sensing element. Of the twenty compounds tested three showed significant EAG responses. These three EAG-active compounds and a negative control were then analyzed for their ability to reduce oviposition via small-cage, two-choice laboratory assays. Two of the three compounds significantly reduced oviposition under laboratory conditions. Lastly, these two compounds were deployed in a field setting in an organic almond orchard in Arbuckle, CA using black egg traps to monitor NOW oviposition. One of these two compounds significantly reduced oviposition on black egg traps under these field conditions. Compound 9 (later identified as isophorone) showed a significant reduction in oviposition in field assays and thus has a potential as a tool to control the navel orangeworm as a pest of almonds. © 2013 Cloonan et al.

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