To cope with a biological invasion, such as Hoplochelus marginalis introduced into Réunion in 1981, implementation of an integrated pest management strategy is crucial in the current socio-environmental context. This paper evaluates the impacts of designing and adopting a biocontrol strategy based on the entomopathogenic fungus Beauveria, developed in collaboration with stakeholders: growers, millers, local organizations (research, development, administrative, etc.), and society. The adopted methodology, called ImpresS by CIRAD, consists in describing the process of an innovation using four interconnected tools: the innovation story, stakeholder mapping, capacity building generated by the innovation, and the impact pathway. The impact pathway model consists in relating the process of the innovation using a factual approach, bringing out the outputs resulting from the innovation, with their outcomes and with their direct and indirect impacts. The description of the process is established using the literature and it is improved using personal and group interviews with growers, local organizations and other stakeholders. The challenge for this approach was to obtain a shared perception of the process by all the stakeholders. The results, based on 70 interviews, showed immediate positive economic impacts for growers, the local sugar sector and the companies distributing the innovation's two products, i.e. Betel® and sporized rice. Another impact is environmental, with no water pollution by an insecticide (chlorpyrifos) that was used before biological control was implemented. Among the indirect impacts, using a successful biological technique with low impact on the environment promoted the quality of sugar marketed internationally, thereby maintaining the subsidy from the European Union. Other impacts were seen at the international level. This retrospective review represents a prototype for other sugar-producing countries to help them in analysing and understanding the a