In Vitro Growth Control Assays of Bacteria Isolated from Lemon Fruit Lesions

Abstract

Citriculture finds favorable climate conditions for its development in the northwest region of the state of São Paulo - Brazil, effectively contributing to the regional economy, generating income for producers and employment for its inhabitants. Citrus cancer is an important disease that affects citrus. Caused by the bacterium Xanthomonascitri, subspecies citri, this phytopathology is spread by the action of nature, contaminated seedlings and mainly human action during cultural treatments. Cancer lesions can be found on leaves, branches, and fruits, and their spread in the orchard can occur to neighboring plants, contaminating the entire cultivated area if proper phytosanitary care is not taken. There is no specific control for citrus cancer, and the use of management techniques and the use of some products that mitigate economic losses are suggested. Among these management practices, we can mention the eradication of the infected plant, preventing it from contaminating the neighborhood. Chemical control uses copper-based products to protect the fruits from injury, bactericides to disinfect the boxes used in the harvest so that there is no greater contamination in the rest of the orchard. In this work, we isolated microorganisms from lesions found in lemon fruits. Samples extracted from the lesions were inoculated in nutrient agar by striatal technique to isolate colonies. After growth, two of these strains were selected for the growth inhibition tests by the minimum concentration in the liquid medium. The results demonstrated the efficiency in growth inhibition when increasing concentrations of peracetic acid and copper were used. Aqueous extracts of pomegranate (Punicagranatum L.) showed a potential inhibitory effect on bacterial growth.