Biocontrol of Alternaria alternata YZU, a causal of stem end rot disease on pitaya, with soil phosphate solubilizing bacteria

Stem end rot is the most destructive disease caused by Alternaria alternata YZU in pitaya-growing regions of Vietnam. This study was conducted to characterize antagonistic phosphate-solubilizing bacteria (PSB) from rhizosphere soil for their biocontrol activities against A. and evaluate effect temperature, pH, water activity on that antagonism. Among seven PSB isolated 45 samples, PSB31 (identified as Bacillus sp. strain IMAU61039, Accession number: MF803700.1) exhibited highest with an average inhibition diameter 0.65 ± 0.05 cm. The results also show controlled mycelial growth secreting antifungal metabolites. potent inhibitory identified under vitro conditions 25 °C, pH 7, aw 1. could be a potential biological control agent YZU.