- Denmark is known for its low use of pesticides. We can share our experience and knowledge about this with other countries in the EU, says senior scientist Lise Nistrup Jørgensen from the Department of Integrated Pest Management at the Faculty of Agricultural Sciences, University of Aarhus.

Exchanging knowledge and ideas is exactly what scientists are doing in ENDURE, an extensive EU project, the main goal of which is to optimise and minimise the use of pesticides.

Together with her European colleagues, senior scientist Lise Nistrup Jørgensen is working with the most important fungal diseases in winter wheat as a case study.

The scientists are gathering information about how best to combat fungal diseases in wheat with as little use of fungicide as possible. They are preparing an overview of damage thresholds, extent of yield loss due to infections with various diseases, and how the diseases can be prevented and treated.

The intention is that the information ”Good practice for disease control in wheat” be made available for farmers, advisors and other interested parties in the countries participating in ENDURE.

- Our hope is that farmers can learn from each other so that we can find out what works out well when you want to become less dependent on fungicides without negatively affecting the yields, says Lise Nistrup Jørgensen.

One of the methods of reducing pesticide use is to grow crops that are disease resistant. Another important element is using reduced and adjusted fungicide dosages dependent on which fungal disease you are up against.

- Danish farmers have a low level of pesticide use, including in wheat, one of the reasons being that they to great degree grow varieties that are resistant to the most important diseases. Denmark is at the forefront in that area. Danish farmers are also good at using reduced dosages. Over the years, Danish farmers have thus reduced their use of fungicides in wheat by more than 50 percent without a negative effect on yields, says Lise Nistrup Jørgensen.

Local differences but shared experience

Not all experience from Denmark can be transferred directly to other countries because there are differences in climate and diseases. In England farmers spray more because the climate is very humid, which can result in serious attacks of the disease septoria. And in France the heat is the culprit. Diseases such as brown rust are liable to be even more serious in areas with a warm climate.

How big the yield in various wheat varieties is and how susceptible they are to various diseases is very dependent on local conditions. Scientists in Denmark and France have tried top quantify how much is necessary or to put it another way – what is the economic optimum.

In Denmark Lise Nistrup Jørgensen has conducted studies with six different wheat varieties that are susceptible to fungal diseases using different control strategies, i.e. more spraying than normal, less spraying than normal, and spraying adjusted to the actual requirements. The aim is to optimise efforts dependent on how resistant the variety is. The damage thresholds in the Danish decision support system Crop Protection Online is one tool that can be used when treatment is to be carried out according to actual requirements.

The French studies aim to clarify treatment requirements in various growing systems. They are looking at how growth factors such as level of fertilisation, growth regulation, and variety affect the need for treatment with fungicides. The results from the French studies show that high levels of fertilisation with nitrogen have the disadvantage of increasing the occurrence of certain fungal diseases. High fertilisation levels also increase the risk of lodging, which can lead to an increased need for using growth retardants.

- Reducing the level of fertilisation in France would be one way of reducing disease pressure and the need for treatment, while in Denmark we are already on a very low level of N use, so there is not much more we can adjust in that way in Denmark, Lise Nistrup Jørgensen warns.

- With increasing grain prices it is often more worthwhile to spray a bit extra to insure yourself against diseases and yield loss. The increases in grain prices we have seen in 2007 mean that the economically optimal treatment with fungicides increases by approximately 50 percent. This is probably the case not only in Denmark, but in all the EU countries. However, despite the increasing grain prices we should still make an effort to limit the use of fungicides as much as possible, says Lise Nistrup Jørgensen and continues:

- The next step in the ENDURE collaboration will hopefully be to establish a common web-based platform showing diseases in wheat. Some of the aims are as follows:

- Create a common ranking of fungicide effects

- Exchange experience about the varieties’ disease resistance

- List information about fungicidal aggressiveness according to plant variety

- Gather knowledge about fungicide resistance

- Fungi do not respect international borders. There is therefore good reasoning in establishing common descriptions, using each other’s experience and avoiding doing the same work twice. There is good experience with this from similar projects such as controlling potato blight, says Lise Nistrup Jørgensen.

Fungicide use for controlling disease in wheat in four EU countries

For more information please contact: Senior scientist Lise Nistrup Jørgensen, Department of Integrated Pest Management, Faculty of Agricultural Sciences, University of Aarhus, telephone: +45 8999 3652, e-mail: LiseN.Jorgensen@agrsci.dk

Facts:

ENDURE, European Network for the Durable Exploitation of Crop Protection Strategies, is a so-called “network of excellence (NoE)” which is financed by EU’s 6th Framework Programme.

The aim of ENDURE is to create a European research network that will also exist after the funding of ENDURE ceases at the end of 2010. The research activities aim to achieve a better understanding of pest biology and the interaction between plants and their pests and, based on this knowledge, to develop new, innovative control strategies in which dependence on effective pesticides is reduced compared to the present. This can be achieved by combining analytical and system-based approaches and by promoting collaboration between biologists, agronomists, economists and sociologists. Another important goal of ENDURE is to ensure that new knowledge is communicated to all relevant parties: farmers, advisers, the industry, politicians and, not least, consumers.

Read more about ENDURE at www.endure-network.eu .

Text: Janne Hansen