Migration of Lettuce Aphid in Australia
Currant-Lettuce aphid (CLA), Nasonovia ribis-nigri, migrated from New Zealand to Tasmania on low-level jet streams in January 2004 and rapidly spread throughout Australia. Like many small winged insects, aphids migrate predominantly via wind and human activity. The distance of their dispersal is influenced by many factors including temperature and weather events.
As part of his PhD with the Cooperative Research Centre for National Plant Biosecurity, Craig Feutrill research is gaining an understanding how these factors interact which is critical to determining the size of quarantine zones. CLA is primarily a contamination pest, which colonises lettuce hearts and rosettes rendering them unsaleable.
A series of six nine-metre suction traps have been constructed including fully automated sampling turntables and steel support structures and three of the five permanent sited traps erected. Two on the north coast of Tasmania and one at Waterloo Corner in South Australia. The final two permanent traps will be at Yanco and near Melbourne. A sixth trap will be mobile mounted on a trailer for placing in ‘hotspots' such as Hay and the Sydney Basin.
The suction traps sample 45 cubic metres of air per minute, which when funnelled down through a fine mesh cone collects flying insects in 70ml sample jars containing polyethylene glycol. The eight jars are replaced weekly and are on an automated turntable, which segregates daily catch samples. Collaborators such as Lionel Hill, Department of Primary Industries, Water and Environment in Tasmania, replace the sample jars on a Monday morning and send them to Craig for sorting and analysis.
The data collected from the traps will be analysed compared to temperature, wind direction and speed and synoptic weather charts to gain an understanding on migration timing and patterns of dispersal.
Craig has also established a working relationship with the New Zealand lettuce aphid researchers to share data from the NZ Aphid-Watch suction trap network.
Ground surveys in most states will augment the suction trap results to establish where CLA resides when not migrating. Although we have some of the weed hosts, the aphid pest can be extremely difficult to find during summer.
For more information, contact Craig Feutrill at craig.feutrill@adelaide.edu.au
Back to The Leaflet.
