Control de oídio ("Podosphaera macularis") y fusariosis ("Fusarium" spp.) en lúpulo y desarrollo de inoculantes de semilla y suelo basados en bioeconomía circular

Résumé

Hops are a perennial plant of great interest in the brewing industry that is seriously affected by powdery mildew (Podosphaera macularis) and Fusarium spp. Many active ingredients have been withdrawn from the Registry of phytosanitary products in the last few years. Their withdrawal has a detrimental effect on the health and economic performance of the crop. The objective of this thesis is to improve the sustainability of hop cultivation with applications that enhance crop health and promote the circular bioeconomy. The main powdery mildew control treatments available on the market have been tested. Zero residue and biological control treatments prevented the development of the disease on leaves. Treatments with potassium hydrogen carbonate, sulfur, and the biocontrol agent Bacillus amyloliquefaciens controlled the leaf disease incidence similarly to conventional products with chemical synthesis products. The use of nanotechnology managed the disease with a 30% reduction in the commercial dose of the chemically synthesized phytosanitary product. These results provide a positive perspective for developing a sustainable alternative to control the disease under field conditions. Hop fields were explored for the presence of autochthonous biocontrol agents. Eleven autochthonous isolates of Trichoderma were evaluated in vitro by direct confrontation and membrane assays to assess their antagonism capacity against Fusarium spp. and in plant trials to evaluate growth promotion. The isolates of T. hamatum T311 and T324, T. virens T312, and T. gamsii T327 showed effective control of the Fusarium isolates evaluated and, together with T. rossicum T328 and T. harzianum T329, promoted hop plantlet growth. Hop harvest residues account for up to 70% of total production. Different residues were tested as inoculants for the development of biological control agents in seed coating. Cone residue powder favored the development of the biocontrol agent T. harzianum T019 and increased the percentage of germination and biomass of the evaluated seeds. The application of this inoculant promotes the circular bioeconomy of the crop, revaluing its residues. With this doctoral thesis, there are two lines of work begging: the exploration of alternative treatments for the control of powdery mildew and fusariosis, and the revaluation of residues that support microorganisms' development for biological control.