DNA techniques for exact detection of pests and diseases

DNA techniques can be used to accurately detect which pests and diseases are present in or around a crop or end product. Sometimes even before the symptoms of the disease are visible. This makes control much more specific and efficient. Scientists of Plant Research International are developing these techniques.

Agriculture and horticulture are working on sustainable crop protection; a system without or with the least possible effects on the environment while giving the plant proper protection. The first step is the detection of pests and diseases in the field or in the greenhouse and precise determination of the amount present on the crop.

DNA techniques are extremely suitable for finding out which organisms are present. It makes no difference where they are: in air, in water, on the crop, in the soil, or in the substrate. This monitoring method enables our scientists - sometimes already within a few hours - to say which organisms are present and how many. And the results are very reliable. And the so-called multiplex detection system allows detection of several species in one test, from fungi to viruses, nematodes and insects.

Bees as monitoring aids

The scientists intend to use bees as ‘employees’ for monitoring harmful fungi and bacteria. Bees fly from plant to plant and probably collect any fungus or bacterium that may be present on the plant. Regular analysis of bees for the presence of pests or diseases can inform the farmer or grower whether a specific harmful pest or disease has arrived in an early stage.

The DNA techniques are suitable for the detection of so-called quarantine organisms. Quarantine organisms are organisms which may not enter the EU. Any batch in which such an organism is found will be destroyed.

In sustainable crop protection DNA techniques are supplementary to other techniques. If these would, e.g., show that plants on a part of the field would suffer from stress, those techniques show which pests and diseases are involved, sometimes even before plant damage becomes visible. If the infestation level is still low, biological products are often sufficient to suppress the pest or disease. And if chemicals would be required, a low dose will be sufficient.

But all this still needs further interrelation: it is often still unknown at which amounts of DNA the organisms are causing damage to the crop and which product or measures the farmer needs to apply. The scientists are working on a combination of monitoring, diagnostics and interrelation in the greenhouse, together with other scientific disciplines.