SOIL-4-CONTROL · Linking plant-soil feedbacks to aboveground-belowground interactions for noxious weed control

Linking plant-soil feedbacks to aboveground-belowground interactions for noxious weed control

The problem Invasive alien species (IAS) form one of the major threats to biodiversity worldwide and drive climate change. SOIL-4-CONTROL assessed possibilities for the control of terrestrial invasive plant species in Europe by combining aboveground herbivores as biological control agents and soil-mediated effects. Biological control uses natural enemies of the target, such as herbivores, for control. This method is widely used on other continents, and is a promising new method for Europe. It remains unexplored if soil communities can also be applied to suppress specific invasive plant species, and if this can strengthen biocontrol. Why is it important for society? The EU Regulation 1143/2014 on IAS emphasizes the urgent need to mitigate the negative impacts of IAS. Authorities and environmental professionals need methods to effectively control already invaded plant populations. Objective Assess possibilities for the control of terrestrial invasive plant species in Europe by combining aboveground herbivory and soil-mediated effects. Conclusions Common ragwort, Jacobaea vulgaris, is a worldwide toxic weed of grasslands rapidly expanding in Europe. No proof has been delivered for the suppression of common ragwort via manipulation of the soil, but soil communities affect common ragwort performance and these effects should be considered when implementing biocontrol and restoration programs. Nematodes seemed unsuitable for the suppression of ragwort, but a bacterium was identified that suppresses common ragwort after root inoculation. This species will be further studied by LU. Common ragweed, Ambrosia artemisiifolia, is an allergenic weed. Field data showed that the accidentally introduced herbivore Ophraella communa strongly reduced seed and pollen production of common ragweed, and has the potential to reduce the health-related costs by 1.1 billion euro annually. Japanese knotweed, Reynoutria japonica, giant knotweed (R. sachalinensis and their hybrid R. x bohemica are a threat to biodiversity and pose large costs to society. The psyllid Aphalara itadori is a specialist herbivore that was candidate for introduction into the Netherlands (NL). A desk study on the risks and benefits of A. itadori was the basis for the petition for release of this population, which was approved by the Dutch government as first exotic weed biocontrol agent in NL. Mesocosm experiments revealed that a recently collected population of A. itadori performs superior on the hybrid.

Data: CORDIS, © European Union