Field Evaluation of green LEDS for Culicoides brevitarsis

Summary

Project Objectives

The objectives of this project were:

• To improve the trapping efficiency of the light traps currently used to provide information to the National Arbovirus Monitoring Program (NAMP) (Kirkland et al. 1995) for defining vector distributions and virus free areas within Australia.
• To demonstrate the effectiveness of green LEDs for trapping a wide range of Culicoides spp (particularly Culicoides brevitarsis) at different locations and under a range of vector densities.
  
  

​​Methodology

Collections of Culicoides species were made using standard light traps. A single green LED trap and an incandescent light trap were to be located at six sites in NSW, the Northern Territory and Western Australia. Four extra traps were located in NSW at sites marginal for C. brevitarsis and Akabane virus making a total of 22 proposed sampling sites. An additional and limited data set was taken in East Timor using incandescent globes and green and blue LEDS. Locations were selected at random from current National Arbovirus Monitoring Program (NAMP) sites and covered a wide range of geographical, climatic and vector density situations. Traps were placed 20 – 30 m apart at a height of 2 m in paddocks containing cattle. Collections were made over two nights, once per month for five months (January to May 2004). The data were all forwarded to the Gosford Horticultural Institute for analysis.

Results New South Wales

Twelve species of Culicoides were recorded from NSW. Counts of seven species were significantly higher in traps with green LEDs. The other five species also exhibited a higher response to green LEDs but this could not be confirmed. There were significantly more C. brevitarsis in the endemic zone and the superiority of the green LEDs was constant inside and outside of the endemic zone.

Northern Territory

Twenty-five species of Culicoides were recorded in the NT. Counts of 12 species were significantly higher in traps with green LEDs. Four species had no significant differences recorded. No analysis was possible on nine species. Of these, four were caught in green LED traps only, one in the incandescent trap only and four in both traps.

East Timor

Although not part of the original objectives, data were also collected from East Timor. This enabled us to test trap efficiency on several exotic species likely to enter Australia. Nineteen species of Culicoides were recorded in East Timor. Counts of 2 species were significantly higher in the traps with the green LEDs. No significant differences were recorded for 8 other species mainly due to statistical problems with the limited data sets. However, counts for all species were numerically higher with green LEDs than with incandescent globes and the blue LEDs. Nine of these species are not currently present in Australia.

Western Australia

Only four sites could be established in WA. Insufficient data were received from WA due to low insect densities and this data set could not be analysed.