Interaction of white grubs, plants and natural enemies

This project studies the interactions between white grubs, host-plants and natural enemies in a soil system to develop and improve a control system for this and other soil pests.

In this project we will:

  1. Select for effective biocontrol means and optimise the application of these natural enemies.
  2. Select and test attractive and repellant plants in a lure&kill and push-pull system.
  3. Select entomopathogenic fungi that are effective and that can survive as root colonizers on luring plant roots.
  4. Select unpalatable plants that protect the crop from oviposition by adult beetles and at the same time repel the grubs from the roots.

Despite the presence/availability of several natural enemies to control pests in soil systems (entomopathogenic nematodes, fungi and predators), the overall control results are still variable and poor for most soil pests. Lack of knowledge about the existing interactions in soil is mostly due to this poor and variable control. Understanding these interactions may provide us with new tools for growers how and when to apply natural enemies in a more efficient way leading to higher and more reliable control of soil pests. For the white grub - plant roots - natural enemies interaction it is our goal to select for effective natural enemies and study the efficacy of these enemies in soil systems. The involvement of semiochemicals in attracting or repelling effects on white grubs and their effects on natural enemies in the soil is part of this study. Integrating aboveground attraction/repellence of the adult beetles to pheromone and plants as part of a system approach to control this pest insect is another goal.


In this project, the cockchafer Melolontha melolontha is the model organism for development of novel control strategies of soil pests in general and this beetle specifically. The new principles of control developed in this project will lead to new approaches of control for many other important soil pest insects.

The results and products in this project specifically are:

  1. Effective biocontrol products and optimised application techniques of existing and new natural enemies.
  2. Attractive and repellant plants applied in a lure&kill and push-pull system that protects the crop from damage.
  3. Root-colonizing entomopathogenic fungi that are effective against the grubs and can survive on the roots for prolonged periods protecting the trees from damage.
  4. Unpalatable plants that prevent oviposition of the adult beetles (aboveground repellence) and repel the grubs from the roots at the same time. These plants prevent new infections and clear it from existing infections with grubs.