Abstract:

Dickeya zeae, the causal agent of bacterial stem rot disease in maize plant, causes disease symptoms such as yellowing and browning of the leaves, softening of the stem, necrosis and bad odour. In this study, the prevalence and biological control possibilities of maize Bacterial Stem Rot disease in Adana and Osmaniye provinces were investigated. The prevalence rates of the disease were determined as 8%, 9% and 40% in Ceyhan, Kozan and Kadirli districts. The incidence rate of the disease was found to be between 8-15%. Bacterial isolates from infected plants were identified as Dickeya sp. using traditional methods, MALDI TOF MS and PCR tests. While the presence of the pathogen could not be detected in soil, it was found in irrigation water. The risk of transmission of the pathogen to healthy fields through irrigation water was revealed in this study. In the biological control of the disease, 332 candidate antagonist bacterial isolates were used and 84 antagonist bacterial isolates were found to have antibacterial activity against Dickeya sp. In semi-in vivo trials on potato slices, six of the 84 isolates caused less decay than the positive control. Two antagonist isolates (X77 and OG/1-12) suppressed decay by 56% and 27%, respectively. These antagonists were identified as species belonging to the genus Bacillus by MALDI TOF MS analysis. The identification of an effective representative antagonist for controlling of Dickeya sp., which has no chemical control, is a promising result in terms of biological control.