Issues facing growers
Invertebrate pests cost Australian grain growers around $360 million in losses each year.
While pesticides reduce losses by more than $1.3 billion each year this comes with a big investment from growers who spend $160 million on control methods annually.
Growers often turn to broad-spectrum insecticides to combat insects such as mites, aphids and caterpillars.
Over time though insects become resistant to the broad spectrum pesticides. With this fast build-up of resistance and ever increasing costs of pesticides what other choices do Australian grain growers have to protect their crops?
Research
In 2009, CSIRO began a Grains Research and Development Corporation-funded research project with the aim to bring an additional option to pest control in the grains sector that promoted sustainability and natural resource management.
The project aimed to answer questions about pests and beneficial insects associated with grain crops such as: where are they found in the cropping landscape? Do they move back and forth between native remnant vegetation and crops and how fast do they arrive to a crop and from where?
Surveys at more than 80 sites were conducted between 2009 and 2013 around Cootamundra in New South Wales, Dalby in Queensland and the Great Southern Region of Western Australia.
Over 30,000 insect samples were collected to help identify the types of habitats on or near grain farms that attracted pests and their predators, track movement between habitats and identify when pests colonise crops.
Strong results over three years showed remnant native vegetation on farms such as bushland including eucalyptus, was more likely to support beneficial insects. Weeds, especially weedy pasture, were more likely to support damaging pest insects.
Impact
Evidence from the research was solid enough to be implemented into integrated pest management strategies by grain growers allowing growers to harness natural pest predators as part of a wider strategy on field, farm and landscape scales.
The GRDC Pest Suppressive Landscapes Fact Sheet was released in 2014 to give growers practical advice on managing native vegetation remnants to encourage beneficial insects and minimise pests.
Example
Affected by drought since 2012, Byron Birch’s 8500 hectares of cropping land in northern New South Wales has been affected by drought since 2012 making him look at inefficient practices to improve production.
Using a dynamic approach to tackle farm issues such as pest management and resources such as GRDC’s Ground Cover, Mr Birch has retained and grown vegetation that encourages beneficial insects.
Research from the CSIRO project shows beneficial insects will move up to 300-400 metres into crops from their native vegetation habitat.
With this knowledge Mr Birch trialled soft chemistry, or target-specific insecticides, on headlands next to native vegetation to encourage the movement of beneficial insects into crops. While it is early days, the initial results look positive.
Future
The CSIRO research has laid the foundation for on-going interest in harnessing the power of pest suppressive landscapes to curb pest impacts on crops and to provide an option to limit reliance on pesticides. It is hoped the reduction of chemical use and building suppressive landscapes will lead to an economic flow to farming enterprises.