Pomegranate (Punica granata L.) Inner Decay Caused by Gluconobacter oxydans Bacterium

Abstract

During the autumn of 2018, inner fruit decay symptoms were observed in pomegranate fruits collected from markets in different localities and farms from Giza, Minia and Assuit Governorates, Egypt. Similar symptoms were observed in each location. The symptoms appeared as creamy bright growth of bacteria in the mesocarp layer, decayed both arils and seeds. Bacteria were isolated from these decayed fruits. The pathogenicity test for isolated bacteria was done. Also, the expressed symptom was compared with the original observed symptoms as followed in Koch postulates. Based on morphological characteristics, analysis of 16S rDNA Genes sequences, and pathogenicity test on pomegranate fruits, the causal agent was identified as Gluconobacter oxydans. Possible control attempts were implemented included applying of essential oils. The results revealed that essential oils of Marjoram, followed by Chamomile expressed the most effective against infection with the bacterium when compared with the control.