Efficacy of azadirachta indica and coleus aromaticus against plant pathogenic bacteria and fungi

Shiney Ramya, B and Ganesh, P

Objectives: To test the efficacy of Azadirachta indica and Coleus aromaticus and to compare them with antibiotics, viz Chloramphenicol and Ketoconazole against Plant pathogens.
Methods: Methanol extracts from two medicinal plants, Azadirachta indica and Coleus aromaticus at 200mg/liter were studied for its biocidal effects on the plant pathogenic bacteria such as Cellulomonas cellulose, Proteus mirabilis and Vibrio vulnificus and plant pathogenic fungi such as Aspergillus niger, Rhizopus solonifer, and Mucor circinelloides. Antimicrobial test was carried out by disc diffusion method. Antibacterial antibiotic, Chloramphenicol at 200mg /liter and antifungal agents, namely ketoconazole at 200 mg/liter were used in the culture susceptibility tests of the identified bacteria and fungi, respectively.
Results: Response varied with plant species and antibiotics. Proteus mirabilis and Vibrio vulnificus were resistant to Medicinal plants. Even though effectiveness of the crude extracts of two different Medicinal plants is significantly high when compared to antibiotics. Cellulomonas cellulose and all the fungal species tested showed effective inhibition by the plant extracts used.
Conclusion: Further studies are required to investigate the bioactive compounds responsible for the activity of plants against pathogens by chromatographic and other advanced methods. It therefore suggests that constituents of the plant extracts could serve as a good source in agricultural field also