Location: Mosquito and Fly ResearchTitle: Evaluation of a push-pull approach for Aedes aegypti(L.) using a novel dispensing system for spatial repellents in the laboratory and in a semi-field environment
|OBERMAYR, ULLA - University Of Regensburg|
|RUTHER, JOACHIM - University Of Regensburg|
|ROSE, ANDREAS - University Of Regensburg|
|GEIER, MARTIN - University Of Regensburg|
Submitted to: PLOS ONE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/15/2015
Publication Date: 6/26/2015
Citation: Obermayr, U., Ruther, J., Bernier, U.R., Rose, A., Geier, M. 2015. Evaluation of a push-pull approach for Aedes aegypti(L.) using a novel dispensing system for spatial repellents in the laboratory and in a semi-field environment. PLoS One. doi: 10.1371/journal.pone.0129878.
Interpretive Summary: Scientists at the USDA-ARS, Center for Medical, Agricultural, and Veterinary Entomology in Gainesville, FL, in collaboration with scientists from the University of Regensburg, Germany and BioGents in Germany, have combined a mosquito trapping system with spatial repellents to better prevent humans and other animals from being bitten. The study was using catnip oil to reduce the amount of attacks by mosquitoes. It was determined that system worked well in laboratory tests, but was not as successful in the semi-field test. Further development will be needed to improve this “push and pull” strategy for outdoor protection people and diversion of mosquitoes and other biting flies to traps. This information will be useful to mosquito researchers and groups that are developing new technologies to protect humans and other animals form arthropods that spread disease.
Technical Abstract: The increase in insecticide resistant mosquito populations necessitates the exploration of novel vector control intervention measures. Push-pull strategies for insect control have been successful when used in integrated crop pest management. Through the combinatory use of deterring and attracting stimuli, the abundance of insect pests can be changed in a given area. A push-pull strategy might also significantly reduce human-vector contacts and augment existing mosquito control strategies, e.g. through the combination of an attractive trapping system and a potent spatial repellent. Our approach includes the BG-Sentinel (BGS) trap in combination with catnip oil (Nepeta cataria), a known spatial repellent for Aedes aegypti. To impart a deterrent effect on mosquitoes at a distance, a homogenous and continuous dispersal of volatile repellent compounds is crucial. We have developed a repellent dispensing system that is easy to use and provides a homogenous dispersal of repellent in an air curtain. The use of five 9 V fans and custom-made repellent sachets containing 10% catnip essential oil created a repellent loaded air curtain that provided coverage of an area of 2 m2 (1.2 x 1.65 m). Air was sampled at four different heights in the curtain and analysed via thermal desorption (TD) and consecutive gas chromatography—mass spectrometry (GC-MS). Nepetalactone, the main constituent of the oil, was detected in air at a concentration range of 80 to 100 µg/m3 and the amounts were comparable at all four sampling positions. When a human volunteer was sitting behind the repellent curtain and a BGS trap was installed in front of the curtain in laboratory push-pull trials, Ae. aegypti landing collections decreased significantly by 50% compared to repellent-free controls. However, in a semi-field environment, comparable protective effects could not be achieved and further research on suitable repellent concentrations for outdoor implementation will be required.