Fresh battle lines have been drawn in the war against insect pests in broadacre crops. Beginning in January, NSW Department of Primary Industries (DPI) entomologist Jo Holloway will begin to find out exactly what's lurking in those crops.

With the support of growers and the Australian Government through the Grains Research and Development Corporation (GRDC) and the Riverine Plains Farming Group she will regularly survey ten farms at various stages of the cropping cycle.

Dr Holloway says we need to gather the basic information needed to develop a system of integrated pest management (IPM), a system where we allow the 'friendlies' in the insect world to do at least some of the control work for us. She points to the success of the system in the horticultural and cotton industries where IPM is now the accepted control method.

Use of insecticides in the cotton industry has been cut by up to two thirds, leading to a switch in research emphasis from pest control to water management. That's good news for farmer's pockets and the environment, but Dr Holloway doesn't expect an easy introduction to broadacre cropping. There are many more variables to contend with such as stubble management, proximity of other crops, and previous pest control strategies. The project won't simply be dealing with one crop and its pests.

Dr Holloway will be surveying the insect population, both friendly and unfriendly, of cereal crops, canola and a pasture phase.

Three times during the growing season the project will gather insects by sweep netting, beat sheeting and vacuum sampling. Dr Holloway anticipates the harvest of a whole range of insects and that sorting them will be a major undertaking, however this sort of background information is essential to get an IPM system up and running.

Suggesting that growers have become increasingly willing to use insecticides to control broadacre crop pests, Dr Holloway says that this has produced its own problems.

Red-legged earth mite is widely recognised as a pest and farmers routinely plan to spray for it, but anecdotal evidence suggests that blue oat mite, which emerges earlier, is missed by that spray and has taken on the role of the earth mite. Growers are more aware of aphids and the danger they pose as carriers of virus diseases. Wheat streak mosaic virus, carried by the wheat curl mite, has shown up again this year with the suggestion that it may be a long term developing problem in some areas.

Dr Holloway says attempting to eliminate one pest sometimes opens the door for another. Fortunately, 'friendlies' tend to be generalists rather than specific in their feeding habits and working them into the control strategy avoids that problem.

An IPM for broadacre cropping won't necessarily mean the end to the use of insecticides but could lead to the use of 'softer' chemicals, less harsh on the whole insect population, and such strategies as the use of boundary crops.

Dr Holloway is confident that if the project can demonstrate the benefits of the system, farmers will adopt it, highlighting the extent to which growers have embraced stubble retention in their systems in recent years.

She also points to successful implementation of IPM strategies in regions of Victoria where local expertise is helping growers to reduce the impact of pests without resorting to pesticides. While the grains industry is a long way behind the horticultural and cotton industries it's the start to collecting the background information that is essential to an IPM. She promises a "hard sell" of the concept at field days and is sure broadacre farmers, who are already monitoring their crops for insect activity, will cooperate.