Bioprotection of pineapple in ecological cropping systems

Monoculture and intensive use of pesticides have reduced the biodiversity of agrosystems and increased the imbalance between pathogenic and beneficial organisms. In the past, pineapple pests were generally controlled by pesticides, but today very few pesticides are authorized. In fragile environments like in the French Antilles, there is a growing public demand for the prevention of environmental risk. Agricultural research is responding by designing new cropping systems based on the ecological intensification of farming practices and alternative ways of managing pests. In Martinique, our strategy is based on agrosystems with increased biodiversity, restored ecosystem functions, enhanced bioregulation and beneficial interactions between plants and microorganisms, including natural defenses (systemic resistance). The aim of our current work is to answer two needs and to confirm several hypotheses:!) reduce pathogenic inoculum by using non-host rotation plants selected for their functional traits (non-host status, biomass production, balanced rhizosphere microflora); 2) select crop cultivars that are able to develop systemic resistance and to adapt their metabolism to environmental changes: we hypothesize a relationship between plant adaptability to biotic (defense genes) and abiotic stresses (genes for cysteine-proteases and their inhibitors, phytocystatins); 3) The reliability of systemic resistance at field level depends ona plant's ability to tolerate pathogens despite abiotic stresses, since such stresses may interfere; 4) Pineapple root system naturally bear diazotrophic bacteria ( endophytic) that are potential inducers of systemic resistance. Finally, we aim to design cropping systems that reduce soil borne pests before the pineapple crop is planted, and to create an environment that subsequently both enables bioregulation and reduces re-infestation of pineapple by the parasite. (Résumé d'auteur