29 August 2006

Key points
� Integrated Pest Management (IPM) can lower spraying costs and achieve higher yields;
� IPM restores the natural balance of insects and improves biodiversity in the area; and
� IPM requires more monitoring of crop systems and knowledge of beneficial and pest insects, parasites and pathogens.

Recent research is challenging the widely held view that modern farming practices, in particular stubble retention and minimum tillage, have led to an increase in pests in Australian crops.

The research being conducted in Western Victoria in conjunction with the national Grain & Graze program, suggests these modern faming techniques are actually killing more pests than ever before. The problem, however, is that beneficial insects, parasites and pathogens are more susceptible to pest control measures than the pest insects, and the balance in Australia's cropping system is being altered.

For Victorian grower Rowan Peel, a desire to restore this balance and create a farm with less reliance on costly chemicals led to a trial of Integrated Pest Management (IPM) on his farm near Winchelsea in the Western Districts of Victoria. Taking an IPM approach has resulted in better crop yields and lower spraying costs.

Mr Peel, a founding member of the Southern Farming Systems group, says the IPM system is generating an increase in the biodiversity on his farm and reducing the environmental impact from his business.

Mr Peel employs three types of IPM control measures on his concept farm, which is also pioneering broad-scale raised bed and alley farming in an area traditionally prone to water logging.

The first control method is naturally occurring insects, parasites and pathogens - called beneficial predators - that act as predators to target pests. The second control measure is to encourage beneficial predators and/or suppress pests in a crop or pasture, and the third is the strategic use of selective or targeted herbicides.

The researcher helping Mr Peel with the trial is Dr Paul Horne from Victorian based IPM Technologies Pty Ltd. He says IPM theories are relatively complex to implement, but the theories behind them are relatively simple.

"For example, growers are able to create a paddock environment where more beneficial species can grow, simply by adjusting insecticide applications," he said.

"This is because the same conditions that harbour pests also provide an ideal habitat for beneficial species.

"We have seen this happen on farms in the Inverleigh (Vic) area, where we have worked for the last three years, as a result of changed insecticide use.

"The ratio of (beneficial) carabid beetles and predatory earwigs to (pest) slugs and earwigs has changed from being dominated by pests to the total population of slugs and earwigs now being 90 per cent beneficial," he said.

This type of population change is a result of changed farming practices - in many cases the best course of action is no action to allow the population of beneficial species to increase. But Dr Horne warns that an increase in crop monitoring and a thorough knowledge of beneficial and pest species is vital to the success of an IPM strategy.

"For IPM to work properly we need knowledge of the life-stages, timing and population dynamics of pests and beneficial species and we must use regular monitoring to decide on what measures are required," he said.

"The rate of build-up of populations of beneficial species can vary greatly. Some (like lacewigs and ladybirds) can be expected to build up numbers very quickly, within a single cropping season.

"Others, like some carabid beetles and spiders, have multi-year life-cycles and can be expected to respond more slowly to a changed management approach.

"Some pests, such as slugs and aphids, can also breed up into large populations rapidly. For example, some slugs can produce a thousands eggs per individual and have two generations per year.

"Aphids can produce young within days of maturing and have a generation time of less than two weeks. Beneficial species such as parasitic wasps and lacewings that specialise in eating aphids also usually have a generation time that is short - like those of the aphids," he said.

Grain & Graze is a joint initiative of Meat and Livestock Australia (MLA), Australian Wool Innovation Limited (AWI), the Grains Research and Development Corporation (GRDC) and Land & Water Australia (LWA).

Further information

The types of beneficials and pests they would be looking for on Mr Peel's property are:

For more information about the National Grain & Graze Program, contact Dr Richard Price, National Coordinator, on 02 6295 6300, mobile 0409 624 297; Gillian Stewart on 02 6263 6042; Lynne Sealie on 02 6263 6021, or visit www.grainandgraze.com.au

Grain & Graze Regional Coordinators

Northern Agricultural Region - Philip Barrett-Lennard - 08 94750753
Avon Region - Linda Leonard - 08 9690 2191
Border Rivers Region - Rachel Charles - 07 4671 7900
Central West/Lachlan Region - Jodie Dean - 02 6895 1015
Corangamite/Glenelg-Hopkins Region - Cam Nicholson - 03 5258 3860
Eyre Peninsula Region - Alison Frischke - 08 8680 6223
Mallee Region - Zubair Shahzad - 03 50 219 103
Murrumbidgee Region - Katrina Sait - 02 6924 4633
Maranoa/Balonne Region - Stephen Ginns - 07 4620 8122