Background

Defined as "the use of living organisms (referred to as biocontrol agents or natural enemies) to prevent or reduce loss or damage caused by pests" (OILB-SROP 1973), biological control is a crop protection method used alternatively or as a complement to other methods (chemical, genetic, mechanical and physical control).

In practice, there are three different strategies:

• Introduction biological control (also known as classical biological control) that aims at the permanent establishment of one or several exotic natural enemies for the sustainable control of a generally exotic plant pest;
• Augmentative (including inoculative and inundative) biological control that consists of releasing biocontrol agents at different frequencies and in different quantities in crops;
• Conservation biological control whose aim is to manage or modify the agrosystem, its surroundings or cultural practices in order to protect and enhance the presence of natural native enemies.

Within this frame,

• the team "Research and Development in Biological Control" more precisely focuses on Introduction and Augmentative strategies;
• the team "Research and Development in Biological Control" also hosts a Biological Resource Centers (BRC) devoted to some egg parasitoids, the BRC “Egg Parasitoids Collection” ( https://www6.inra.fr/crb-eggparasitoids-coll ).

Research topics and objectives

The implementation of these projects is based on several sequential steps:

• Inventory of the natural enemies;
• Molecular characterization of biocontrol agents;
• Evaluation of the rearing possibilities of the biocontrol agents;
• Inter- or intraspecific comparisons of the biological features, particularly in terms of host specificity, life history traits or responses to major abiotic or biotic factors;
• Validation of the efficiency of the chosen biocontrol agents in semi-field or field conditions;
• Optimisation of release strategies (number, frequency, composition, positioning over time or space).

In addition to this work on the biocontrol agents, we also focus on the biology and ecology of the hosts or preys

• Molecular characterization and development of identification tools;
• Rearing of the target pest as well as of non-target or substitute species;
• Demography and ecology of the pestin the field.

Within the framework of this optimisation approach, the team also tries to identify and test the generic mechanisms linked to the success or failure of biological control. To do so, we establish research partnerships with more basic research.

Biological models studied

Introduction (classical) biological control

• Field releases of Mastrus ridens against the apple codling moth, Cydia pomonella;
• Evaluation of exotic parasitoids (genus Ganaspis) against the spotted wing Drosophila suzukii;
• Assessment ot the possible introduction of egg parasitoids (genus Trissolcus) against the brown marmorated stink bug, Halyomorpha halys.

Augmentative biological control

• Evaluation of native parasitoids against various phytophagous stink bugs (including Nezara viridula et Eurydema sp);
• Evaluation / Optimization of predatory bugs (genus Macrolophus);
• Evaluation of the ladybird Rhizobius lophantae against the scale insect Pseudaulacaspis pentagona in blackcurrent crops;
• Survey of scale insects and associated natural enemies in horticultural crops.

BRC « Egg Parasitoids Collection »

• Survey of the Trichogramma species in various habitats;
• Integrative characterization of the genus Trichogramma;
• Evaluation of new methods of phenotyping.