FacultyNewsSciencePublicationsJobs and educationBusiness cooperationContact

Biological protection against fungal diseases in plants

Scientists use nature’s own remedies to combat plant diseases.

Microscopic battles are fought in and around plants. The soldiers on both sides are fungi. On the one side are the plant pathogens such as grey mould, which cause plant diseases. On the other side are disease-inhibiting fungi such as mycorrhiza fungi, that live together with the roots of the plants, and the antagonist Ulocladium atrum, that can be added to the leaves.

Scientists at the Faculty of Agricultural Sciences (DJF) at the University of Aarhus act as the generals. With their knowledge of which fungi work best, how they work and which effects the particular protection programme has, the researchers can create a good overview and can plan the right strategy.

- We use nature’s own resources to practise biological protection instead of chemical protection against plant diseases. There are two ways to do it. Either you can promote the natural processes around the plant or you can inoculate the plant with known biological remedies such as mycorrhiza fungi and antagonists, explains senior scientist John Larsen from the Department of Integrated Pest Management at the Faculty of Agricultural Sciences at University of Aarhus.

Mycorrhizae are fungi that occur naturally in the soil and that live on plant roots in harmony with the plant. Scientists and gardeners take advantage of this symbiotic relationship to combat harmful fungi in the plants.

In closed systems such as greenhouses you can add biological remedies while open systems, such as fields, can to a greater degree take advantage of the natural regulation mechanisms found in the soil and the plant by promoting them through various growing systems.

Strawberry war against fungus

However, it can be necessary to add remedies to crops in the field, such as is the case with strawberries.

In one of the research projects the scientists are investigating the relationship between added antagonists and naturally-occurring micro-organisms on the plant, which can also inhibit fungal growth. The studies are being undertaken at organic and conventional strawberry growers spread throughout Denmark.

By gaining knowledge of natural conditions scientists will be better able to evaluate possible positive and negative effects of adding mycorrhiza and antagonists. They can also put together an improved plant protection programme.

- By investigating which biological and chemical remedies work well together we can prepare an integrated treatment programme and perhaps have fewer spray treatments. You could imagine, for example, that you start off by spraying with a fungicide so the competitors are removed from action. That would mean that the beneficial biological remedies can gain a better foothold, explains John Larsen. The scientists have found several examples of antagonists that are not affected by fungicides, which is a promising result.

For more information please contact: Senior scientist John Larsen, Department of Integrated Pest Management, Faculty of Agricultural Sciences, University of Aarhus, telephone: +45 8999 3659, e-mail: [email protected]

Wednesday 09 May 2007 | Communication Unit