If left untreated, cereal diseases can have a devastating effect on crop yield and quality potential.

Bayer CropScience seed treatment development manager Anthony De Monte, speaking at the recent GRDC-sponsored Cereal Foliar Disease Workshop at Clare, recently made the point that seed treatments and foliar fungicides both had an integral role to play in a management strategy for the control of cereal diseases.

The aims of an integrated seed and foliar disease management strategy are to delay any disease onset, manage the disease expression and to maximise the crop potential, he told the 200 strong audience of scientists, researchers and farmers.

However, the use of seed treatments and fungicides alone cannot overcome the issues caused by poor agronomic practices, so fungicides should form just part of an overall integrated disease management strategy.

Before sowing, it is necessary to identify the risks to the crops in the season ahead and the most important elements of an integrated approach for disease management should be reviewed.

This review should include:

• farm hygiene, including: tillage practices (stubble management);
• herbicide use (control of volunteer/host plants);
• use of resistant varieties for diseases identified as major risks;
• appropriate crop rotation to reduce potential disease problems;
• sowing time to reduce the favourability of disease development; and
• use of chemical control as determined by the risks identified.

• suppress or control the pathogen;
• maximise green leaf area;
• maintain active crop growth; and
• reduce build-up of disease inoculum.

Treating seed is a little like vaccination, if it's not done, there is an unnecessary risk taken of the crop developing disease. This is particularly true of smut diseases that cannot be treated once the crop is sown. Also, the use of an effective systemic seed treatment will provide protection against early foliar infections of many diseases.

Seed treatment fungicides offer cost effective insurance against many pathogens and should form the basis of an integrated disease management strategy.

What is done early for disease management sets the scene for the rest of the cropping period. Use of a seed treatment will make a valuable contribution to the future health of a crop, but it certainly will not last throughout the growing period.

Fungicides applied to fertilisers will significantly extend the period of control, however it is important that vigilance is maintained once the crop emerges. Regular checks enable the prompt detection of any disease that affects the health of the plant. The earlier a disease is detected, the greater the chance of managing it.

Although the use of a seed treatment will delay the onset of disease by providing control and/or suppression of many diseases for a period time, growers must be alert to the need to supplement this with the application of foliar fungicides. When used in conjunction with a seed treatment, foliar fungicides will be primarily used to protect the crop against mid to late season infections.

The product chosen will be based on the diseases present and stage of development and while it is difficult to quantify any exact period of protection for any product, a number of factors will influence it. These include the choice of product itself, effective coverage, speed of plant growth, fungicide availability to the plant, inoculum levels and onset of infection.