Western Australian tomato growers are being asked to check their crops for signs of disease after potato spindle tuber viroid (PSTVd) was confirmed on a single plant in a crop in Carnarvon.

The disease was detected by the Department of Agriculture and Food during regular surveillance activities in the region.

As PSTVd is an exotic disease to Australia, the Department is working with the Office of the Chief Plant Protection Officer and the national Consultative Committee for Emergency Plant Pests on the management of this incident.

All plants in the infected block have been destroyed, and surveillance has been carried out on neighbouring paddocks, with no further signs of the disease found.

The Department has prepared a response plan necessary for further surveillance, containment and eradication of this exotic disease.

Department horticulture development officer John Burt said PSTVd could have a potentially serious impact on both the tomato and potato industries.

“Potentially the virus can reduce fruit yield in tomatoes by up to 50 per cent and in potatoes tuber yield loss could be as high as 65 per cent,” Mr Burt said

“Symptoms of PSTVd could be confused with nutrient imbalance, spray damage and insect damage.

“In mature tomato plants signs include purpling and yellowing of the leaves, shortening of leaf internodes, which result in a bunching effect and leaf curling and twisting.

“Plant growth may also appear stunted, spindly shoot growth can occur and fruit will fail to ripen.”

Mr Burt said it was very important for growers to check their plants, as secondary transmission of the disease occurred easily through contact with or handling of the plants.

“This includes movement of animals and machinery through the crop, cutting tools and even clothing worn in the paddock”.

There have been previous detections of PSTVd in Australia, including in Western Australia. The most recent case in WA was in a greenhouse in Muchea in 2004.  All incursions have been successfully eradicated.

A factsheet on potato spindle tuber viroid is available from Department offices or on-line at www.agric.wa.gov.au, searching under the virus name.

Any growers who suspect they have signs of PSTVd in their crops, should contact the Department’s Pest and Disease Information Service on freecall 1800 084 881.