Evaluation of a mosquito control intervention and recommendations for development of best practice protocols by the Shire of Kalamunda

The mosquito control program implemented by the Shire of Kalamunda Environmental Health Service has been assessed. Mosquito species and abundance has been evaluated along with an assessment on the current level of pesticide resistance and downstream S‐methoprene levels post‐treatment. The rate of Ross River virus transmission within the Shire has also been considered, along with the relationship between local species and virus transmission. Methodology Floating Emergence Traps were used in 15 storm‐water gullies to determine the effectiveness of S‐methoprene briquets in prevention of adult mosquito emergence over 124 days. Samples were taken monthly from October 2014 to March 2015. Two treatment methods were assessed, application of briquet using a float, and application without a float. These were compared to untreated control gullies. The productivity of gullies was also assessed. Twenty‐five carbon dioxide light traps were deployed in a treatment area and repeated in a control area. The treatment and control areas were reversed and sampled again the following season to allow for inter‐area baseline and seasonal differences. Nine water samples were taken and analysed for the presence of S‐methoprene. Samples were taken from the outlet of chains of storm‐water gullies during the first rainfall following application of S‐methoprene briquets in the area. Results Storm‐water gullies have been confirmed as a significant source of mosquito breeding and are likely to be increasing the spread of Ross River virus in the area in which they are located. Mosquito breeding peaks in early November, and decreases by February as the hot dry conditions prevent large scale breeding for all species. Gullies produced a mean of 108 mosquitoes per day over the season. Culex quinquefasciatus and Aedes notoscriptus are the most abundant species within the Shire at all times in the season. Numbers of C. quinquefasciatus emerging can exceed 1600 per day per gully. A. notoscriptus