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Universidad de Córdoba (2018)

Potencial de la desinfestación química del agua de riego y/o suelo para el control de la Verticilosis del olivo

Gómez Gálvez, Francisco Jesús

Titre : Potencial de la desinfestación química del agua de riego y/o suelo para el control de la Verticilosis del olivo

Potential of chemical disinfestation of irrigation water and/or soil for controlling Verticillium wilt of olive

Auteur : Gómez Gálvez, Francisco Jesús

Université de soutenance : Universidad de Córdoba

Grade : Tesis Doctoral 2018

Résumé partiel
The infestation of irrigation waters by Verticillium dahliae poses a risk for the health of susceptible crops in Andalusia. Spread of conidia and sclerotia of the pathogen via irrigation water has contributed to enlarge the extension and epidemic development of the Verticillium wilt of olive (VWO) throughout this region. The application of chemical disinfectants into the irrigation water has proved to be useful suppressing infestations by V. dahliae conidia. To ascertain the effect against sclerotia -more persistent structures of the fungus- is required before recommending this practice as an exclusion measure within the integrated management of the VWO. Furthermore, the fate of this treated water would be the rhizosphere, so this measure could contribute to eradicate the fungus in the soil and/or reduce the disease in infested olive orchards. The first goal of the present thesis was to evaluate the in vitro efficacy of chemical disinfestation in preventing and eradicating water infestations by V. dahliae sclerotia. Three products differing in composition (OX-VIRIN®, OX-AGUA AL25®, and Deccoklor®) were tested according to the concentration, V. dahliae isolate and time of action. The effect of disinfectants OX-VIRIN® (OV) and OXAGUA AL25® (OA), both including hydrogen peroxide in their formulation, varied with the concentration and time. Suppressive efficacy ranged between 87.8- 100% for the three highest concentrations of OV (3.2-51.2 mL L-1) and 99.6-100% for the two highest of OA (0.4175 y 1.2525 mL L-1) at 5-30 days after the treatment of infested water. These OV concentrations showed higher preventive efficacy than OA concentrations against infestations carried out 30 days after the chemical treatment of the water (97-100% vs. 68,9-100%). The chlorinated product Deccoklor® was ineffective. The potential efficacy of OV and OA in reducing the fungus in the soil and the VO in young olive plants was evaluated in several experiments conducted under growth chamber conditions. The soil-applied disinfectant treatments were also assessed for phytotoxicity on olive plants. Susceptible olive cultivars were grown in V. dahliae-infested soil and subjected to different disinfectant treatments with OV- or OA-treated water. The lowest concentrations recommended for disinfesting V. dahliae-containing water according to results from the previous objective were used (3.2 mL L−1 or 0.4175 mL L−1, respectively). The weekly and monthly treatments with OV and the biweekly treatment with OA decreased solidly the total inoculum density in the soil up to 21.3-29.6% and sclerotia density up to 65.6-91.2%, depending on the treatment.

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Page publiée le 13 février 2019