Interstate quarantine measures for the wheat streak mosaic virus (WSMV) in Western Australia will end this week.

The Department of Agriculture and Food’s Deputy Director General (Biosecurity and Research) Rob Delane said today that the industry GrainGuard committee has unanimously supported the Department’s conclusion that any form of practical containment is not possible.

A surveillance programme by the Department detected the virus in volunteer wheat on three properties in the Western Australian wheatbelt earlier this month.  Two of the locations were in the Esperance region and the other was in the Kondinin Shire.

Mr Delane, said further sampling during intensive trace back of infected grain had identified additional infected properties, and the presence of the virus in up to six wheat varieties.

Grain industry representatives Ray Marshall from Western Australian Farmers and Barry Large from Pastoralists and Graziers Association confirmed the outcome of the meeting.

“We have assessed the situation based on the facts, and unfortunately, we could not come to any other conclusion” Mr Large said.

“The Department and the GrainGuard committee has come under intense pressure over this issue, but have come to the right decision at the right time,” added Mr Large.

Varieties from which positive detections were obtained include Wyalkatchem in the Kondinin/Kulin area and Wylah, Sapphire, Marombi, Cascade and H45 in the Esperance region.

Mr Delane said it was thought the virus had entered Western Australia from interstate several years ago as seed borne infection in wheat varieties, and had been spread by the wheat curl mite, a known vector of the virus and present in Western Australia.

“At this stage we do not expect wheat streak mosaic virus to be widespread across the wheatbelt as it appears to be a relatively recent introduction.  Many areas in the northern growing regions are likely to be relatively free from the virus at this stage. However, further surveillance sampling will be conducted this year,” Mr Delane said.

“The virus has also not yet been detected on other grass species.

“Growers are advised to continue with their winter program.  It was recommended that they control any volunteer green bridge material that may assist the mite vector to persist into the winter growing period,” he said.

Mr Delane said the impact of WSMV in Western Australian conditions had yet to be fully assessed.  “While the Department hopes that the disease was relatively benign, we believe the evidence points to a likelihood that WSMV will have a significant impact in some seasons and situations”.

A seed test for WSMV is not currently available. However, Mr Delane said it was the focus of a research project being funded by GRDC.  It was hoped that a test would be developed soon to allow growers to test seed for WSMV from 2007.

“Farming practices remain the key to reducing the rate of spread of the virus in Western Australia,” he said.

Mr Delane said that dealing with WSMV had proved particularly challenging and have required close collaboration of scientific and regulatory staff, breeding and seed companies and grain industry representatives.  The professionalism and collaboration has been a credit to all involved.