Knowledge about the western corn rootworm Diabrotica virgifera in order to develop an efficient and integrated pest management strategy in Flanders (DIABROTICA)

The research project DIABROTICA is about the western corn rootworm, Diabrotica virgifera, a very harmful beetle pest of maize. Through annual monitoring, we aim for an early detection of this beetle species in Belgium to avoid its permanent establishment. The western corn rootworm is a beetle of American origin that ended up in Serbia via military air traffic in the 1990s and has been spreading gradually within Europe since then.

The larvae of this beetle feed on the roots of maize plants and, particularly in monoculture maize fields, average yield losses can increase from 6.5 to 13%. In 2003 and 2004, a few dozens of beetles were detected near Zaventem airport. The European emergency measures that were implemented at that time could successfully stop the invasion. After a 10-year-pause, the western corn rootworm was again observed near Zaventem in 2014. An intensive monitoring campaign with pheromone traps is now being set up every year. In 2015 and 2016, no "new" beetles were detected. In 2017, western corn rootworms were detected again, both in Zaventem, and - for the first time since the start of the monitoring campaign  (2003) - in Rumst.

One of the basic principles of an integrated approach (IPM) is early detection of the pest so that action can be taken quickly. A network of approximately 30 high-risk locations spread throughout Flanders (airports, approach routes from the south, etc.) has been created and is being used to set an annual pheromone trap based monitoring campaign. In the vicinity of Zaventem and Rumst, several new locations will be monitored from 2018 onwards. From mid-July to the beginning of October, one or more pheromone traps are placed, depending on the field size. These traps are replaced regularly and are checked for the presence of this harmful beetle at the ILVO Diagnostic Centre for Plants. Once detected, farmers are informed and measures are being imposed.

The "comeback" of the harmful western corn rootworm and the detection outside its "normal" region is forcing our country to develop a control strategy. In the meanwhile, the quarantine status and the European emergency measures have been lifted. At EU level, we are requested to develop an "Integrated Pest Management" strategy. In this context, the "Task Force Diabrotica" was established. This is a working group of stakeholders that consults on a regular basis and sets out the guidelines for keeping this harmful beetle under control. From the start, farmers have been involved in the annual monitoring. They are also kept informed about the results through meetings so that they can apply the recommended control measures to their own farm.