DEET (N,N-diethyl-meta-toluamide)/PMD (para-menthane-3,8-diol) repellent-treated mesh increases Culicoides catches in light traps

• Published in: Parasitology research (1987) Vol. 115; no. 9; pp. 3543 - 3549
• Main Authors: Murchie, A. K., Clawson, S., Rea, I., Forsythe, I. W. N., Gordon, A. W., Jess, S.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.09.2016
• Subjects: Animals; application rate; bendiocarb; bioassays; Biomedical and Life Sciences; Biomedicine; bluetongue; Bluetongue - transmission; buildings; cages; Ceratopogonidae - drug effects; Ceratopogonidae - virology; Culicoides; Cyclohexane Monoterpenes; deet; DEET - pharmacology; dose response; ethics; experimental design; Immunology; Insect Repellents - pharmacology; Insect Vectors - drug effects; Insecticides - pharmacology; lambda-cyhalothrin; light traps; livestock; Medical Microbiology; Menthol - analogs & derivatives; Menthol - pharmacology; Microbiology; midges; Nitriles - pharmacology; Original Paper; Phenylcarbamates - pharmacology; Plant Extracts - pharmacology; Pyrethrins - pharmacology; repellents; screening; Sheep; Terpenes - pharmacology; terpenoids; viruses; Attractant; Repellent; Menthane-3,8-diol; Onderstepoort light trap; DEET; p-Menthane-3,8-diol; Culicoides
• ISSN: 0932-0113; 1432-1955
• DOI: 10.1007/s00436-016-5119-x

Biting midges ( Culicoides spp.) are vectors of bluetongue and Schmallenberg viruses. Treatment of mesh barriers is a common method for preventing insect-vectored diseases and has been proposed as a means of limiting Culicoides ingression into buildings or livestock transporters. Assessments using animals are costly, logistically difficult and subject to ethical approval. Therefore, initial screening of test repellents/insecticides was made by applying treatments to mesh (2 mm) cages surrounding Onderstepoort light traps. Five commercial treatments were applied to cages as per manufacturers’ application rates: control (water), bendiocarb, DEET/ p -menthane-3,8-diol (PMD) repellent, Flygo (a terpenoid based repellent) and lambda-cyhalothrin. The experimental design was a 5 × 5 Latin square, replicated in time and repeated twice. Incongruously, the traps surrounded by DEET/PMD repellent-treated mesh caught three to four times more Obsoletus group Culicoides (the commonest midge group) than the other treatments. A proposed hypothesis is that Obsoletus group Culicoides are showing a dose response to DEET/PMD, being attracted at low concentrations and repelled at higher concentrations but that the strong light attraction from the Onderstepoort trap was sufficient to overcome close-range repellence. This study does not imply that DEET/PMD is an ineffective repellent for Culicoides midges in the presence of an animal but rather that caution should be applied to the interpretation of light trap bioassays.