Approches de la nuisibilité du bleuet en colza d'hiver

Infestation of oilseed rape fields by cornflower is more and more frequent, which could become harmful. In contrast, cornflower produces nectar that is a resource for pollinators and probably crop pest predators and parasitoides. In order to get benefit of this resource, it is necessary to determine a balanced equilibrium between the services and the weediness of cornflower in spite of destroying it. We describe here bispecific competition trials against oilseed rape in small experimental plots. Experimental conditions led to too high or too small plant densities to estimate a threshold of competition. Results provide relevant information on self-concurrence among cornflower plants and on i…