Abstract
Tomato production in Côte d'Ivoire faces many constraints. The post-harvest conservation of tomatoes in southern countries is a significant obstacle that must be overcome. The present study was conducted with a view to developing and proposing to operators in the tomato sector innovative conservation techniques adapted to their production context. The methodology was based on the application of cold, a hexanal-based treatment and a natural antifungal agent. The study showed the antifungal power of the plant Ocimum gratissimum L. on several tomato pathogens. The essential oil at a concentration of 750 ppm inhibited 100% of the growth of Fusarium, Alternaria and Botrytis. The decoction of the same plant inhibited fungal growth by more than 90%. Concerning the post-harvest conditions, the results showed that the appropriate harvest stage for the conservation of tomato with the different treatments is the Breaker stage. Indeed, this stage has the longest shelf life. Post-harvest treatment of tomato fruits with a hexanal solution and a combination of hexanal and O. gratissimum L did not control rots during tomato storage. However, it should be noted that the quality parameters of the tomatoes were not affected compared to those ripened in the field. Formulations based on Ocimum gratissimum were also tested in pre-harvest against alternaria, which we have shown to be very prevalent in the crop. The results in situ and in planta showed a slowing down of the development of the disease in the curative phase and a total absence when applied as a preventive measure on tomato plants. Therefore, Ocimum tea can be used as a preventive treatment on tomato plants. From this study, it appears that the application of post-harvest treatments is not very effective and that an alternative is to treat tomato plants with Ocimum tea in the field to prevent early blight. The fungal reduction of the pathogen load of the fruits could contribute to limit the post-harvest losses.