14 June 2002
Further detections of Lettuce Aphid discovered
The Ministry of Agriculture and Forestry (MAF) has received confirmation that the Lettuce aphid Nasonovia ribis-nigi
has spread to Pukekohe and Outram near Dunedin.
Barney Stephenson, MAF's National Adviser on Plant Pest Surveillance and Response said that Crop and Food Research
reported these new detections to MAF earlier this week.
"The spread of this pest has been faster than expected, but we always knew that it was only a matter of time.
"Aphids reproduce very rapidly and are very efficiently dispersed over significant distances by the wind. Its arrival
in Auckland is not likely to be associated with movement of produce," he said.
Dr Stephenson praised the initiatives undertaken by VegFed in alerting their growers to the existence of the aphid
after it was first discovered in Marshlands near Christchurch in early April this year, and also for providing them with
information on controlling the pest.
"Eradication of this pest is not feasible. Within several days of its detection, it had a confirmed distribution of
over 1000 square kilometres, which included Christchurch city. The lettuce industry now needs to take steps to manage
the pest, which would include short term control measures, and development of a long term integrated approach".
VegFed are working with Crop and Food Research and chemical companies in order to obtain clearance for a wider range of
chemicals and to provide growers with advice on immediate control.
Dr Stephenson said the lettuce aphid also infests blackcurrant and gooseberry bushes but it is particularly bad in
lettuces because the aphid gets in to the heart of the plant, making it difficult to control.
These latest finds bring the distribution of the aphid to Auckland, North Canterbury and Dunedin.