Examinando por Materia "Bacillus"

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Effect of co-inoculation with growth-promoting bacteria and arbuscular Mycorrhizae on growth of Persea americana seedlings infected with Phytophthora cinnamomi
(MDPI, 2024-04-02) Solórzano Acosta, Richard Andi; Toro García, Marcia; Zúñiga Dávila, Doris Elizabeth
Avocado is one of the most in-demand fruits worldwide and the trend towards its sustainable production, regulated by international standards, is increasing. One of the most economically important diseases is root rot, caused by Phythopthora cinnamomi. Regarding this problem, antagonistic microorganism use is an interesting alternative due to their phytopathogen control efficiency. Therefore, the interaction of arbuscular mycorrhizal fungi of the phylum Glomeromycota, native to the Peruvian coast (GWI) and jungle (GFI), and avocado rhizospheric bacteria, Bacillus subtilis and Pseudomonas putida, was evaluated in terms of their biocontrol capacity against P. cinnamomi in the “Zutano” variety of avocado plants. The results showed that the GWI and Bacillus subtilis combination increased the root exploration surface by 466.36%. P. putida increased aerial biomass by 360.44% and B. subtilis increased root biomass by 433.85%. Likewise, P. putida rhizobacteria showed the highest nitrogen (24.60 mg ∙ g−1 DM) and sulfur (2.60 mg ∙ g−1 DM) concentrations at a foliar level. The combination of GWI and Bacillus subtilis was the treatment that presented the highest calcium (16.00 mg ∙ g−1 DM) and magnesium (8.80 mg ∙ g−1 DM) concentrations. The microorganisms’ multifunctionality reduced disease severity by 85 to 90% due to the interaction between mycorrhizae and rhizobacteria. In conclusion, the use of growth promoting microorganisms that are antagonistic to P. cinnamomi represents a potential strategy for sustainable management of avocado cultivation.
Efficiency of entomopathogenic bacteria and fungi on Oligonychus yothersi in vitro and on Persea americana Mill. plants
(Facultad de Agronomía de la Universidad del Zulia,, 2023-11-03) Parco Quinchori, Jhimy Andy; Valverde Rodriguez, Agustina; Cornejo, Antonio; Briceño, Henry; Barrionuevo, Laura; Romero, Javier
In the germplasm bank of 22 varieties of avocado (Persea Americana Mill.) belonging to the Fruit Horticultural Institute Investigation, HermilioValdizan National University (UNHEVAL)-Peru, it is common to observe a high population of the species Oligonychusyothersi, a phytophagous mite harmful to the crop. Controls with commercial acaricides are restricted in place, due to the presence of beehives installed in adjacent plots. The objective of this study was to evaluate the effect of four commercial formulations containing strains of Metarhiziumanisopliae and Beauveria bassiana and the toxins of Bacillussubtilis, Bacillus thuringiensis var.kurstaki (Btk) for the control of O. yothersi. The entomopathogenic products were evaluated in the field applying a randomized complete block design with five treatments and three replicates. In the laboratory, 500 adult mites were selected, placing 100 mites per Petri dish with three repetitions per treatment. It was found that the formulation Bacillus thuringiensis var.kurstaki under field conditions reduced the population incidence of mites by up to 98.07% in 49 days. In the laboratory, the B. subtilis and M. anisopliae formulations caused 100% mortality six days after application proving to be efficient control alternatives.