Act early to reduce canola virus risk this coming season
Grain growers in the southern cropping region are encouraged to implement early management practices ahead of the 2015 cropping season to reduce the risk of aphid infestations and associated diseases.
Crop insect pest and disease experts, supported by the Grains Research and Development Corporation (GRDC), advise that strategies put in place now will help to discourage aphid population build-up and the potential for crop diseases, especially beet western yellows virus (BWYV), during the growing season.
They say eliminating the green bridge – weeds and volunteer crops which can host large populations of insects as well as viruses between growing seasons – is a key component of a risk reduction plan.
To assist growers with their management strategies, the GRDC has collaborated with cesar, the South Australian Research and Development Institute (SARDI) which is a division of Primary Industries and Regions South Australia (PIRSA), the New South Wales Department of Primary Industries (NSW DPI) and the Victorian Department of Economic Development, Jobs, Transport and Resources (DEDJTR) to produce a new Reducing aphid and virus risk – tips and tactics publication.
The publication, available via www.grdc.com.au/GRDC-TT-ReducingAphidVirus has been released in response to last season’s canola crop losses caused by BWYV across the Lower North, Mid North and Eyre Peninsula in SA, western Victoria and some parts of NSW.
Entomologist Paul Umina of cesar says widespread infestations of green peach aphid (GPA) contributed to the 2014 outbreak of BWYV, which is transferred into canola crops by aphids carrying the virus. Several aphid species transmit BWYV, but GPA (which has a high prevalence of resistance to insecticides) is the principal vector and the most common species on juvenile canola plants.
Dr Umina says early management decisions will place growers in a favourable position to limit potential damage from BWYV in 2015.
“Although the prospect of another BWYV outbreak occurring this season is low, there are a number of measures growers can take over the coming months to lessen the likelihood of aphid infestation and disease,” Dr Umina said.
These management recommendations, especially for growers when sowing in conditions of high virus risk, are contained in the new publication and include:
• Destroy the green bridge over summer and autumn prior to sowing
• Do not sow canola into desiccating weeds/canola volunteers, otherwise, aphids will move directly from the weeds to the emerging seedlings
• Use seed treated with a neonicotinoid insecticide and ensure proper application and coverage of seed dressing for efficacy against GPA
• Monitor for virus and GPA populations on weeds, volunteers and seedling canola crops
• Ensure correct identification of GPA before deciding on control strategies. A GRDC Back Pocket Guide, www.grdc.com.au/CropAphidsBackPocketGuide, to aid in the identification of crop aphids has recently been developed.
Meanwhile, GRDC-funded research continues into pesticide resistance in GPA and the management of BWYV.
An industry-endorsed Resistance Management Strategy for GPA in Australian grains was launched last year and can be downloaded via www.grdc.com.au/GreenPeachAphidResistanceStrategy.
The GRDC also last year announced an emergency funding package of $315,000 in response to the outbreak of BWYV in canola crops in the southern region.
SARDI plant pathologist Jenny Davidson said this funding was and will be used in a number of areas, including forensic analysis of canola paddocks; communication to growers and advisers (assisted in SA with an additional $40,000 in emergency funding provided by SAGIT); and preliminary assessment of virus levels in different canola varieties to identify if there are any useful levels of resistance to BWYV for future sowing recommendations.
“Through GRDC’s existing investments in virology, a number of other activities are being undertaken to assist in further understanding of last year’s BWYV outbreak,” Dr Davidson said.
Paul Umina, cesar
03 9349 4723
Jenny Davidson, SARDI
08 8303 9389
Bill Kimber, SARDI
08 8303 9536
0409 675 100
Caption: Typical symptoms of BWYV in canola. Photo: Mick Faulkner.
GRDC Project Code CES00001, CES00002, DAS00151, DAV0119
Region South, North