Antagonistic activity of Pseudomonas donghuensis and Bacillus subtilis for the management of “Damping off” phytopathogens of the chile crop.

Abstract

The effectiveness of the Bacillus subtilis and Pseudomonas donghuensis strains for the
control of Fusarium oxysporum and Pythium aphanidermatum, which cause the drowning of chili seedlings in the greenhouse, was evaluated. Its pathogenicity to cause the disease was verified and antagonism tests were obtained in culture plates with enriched PDA. Through the in vitro confrontation of these phytopathogens with three strains of the species Bacillus subtilis, it was observed that this sporulate has the capacity to inhibit to a greater or lesser degree (39.35- 56.24 %) the mycelial growth of F. oxysporum, but not the from P. aphanidermatum, none of the Bacillus isolates used in this study had an effect in inhibiting this Oomycete, since it grew faster than the spore-forming bacteria, since P. aphanidermatum developed and grew to fill the culture plate in just 36 hours. On the other hand, P. donghuensis inhibited the growth of this last phytopathogen by 56 %, however, it did not present an inhibition effect against F. oxysporum, so it could be feasible to use mixtures of these two antagonists for the management of this disease and be able to control Damping off problems caused by these phytopathogens.