Encountering the effects of Leaf Spot (Alternaria polianthi) on Tuberose (Polianthes tuberosa) by Biocontrol agents, Plant extracts, and Plant Oils

Author: P. Mahalakshmi, M. Ayyandurai and P. Mareeswari

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Abstract

Tuberose is an ornamental crop grown in tropical and subtropical areas. The incidence of leaf spot disease caused by the fungal pathogen Alternaria polianthi is a severe problem that leads to reduced growth, yield loss, and is triggered by high temperature and humidity. In response, a survey was conducted in the farmers' fields in Melachinnanampatti village, Alanganallur block, Madurai district, which recorded a maximum disease incidence of 50.34%. To manage the pathogen, bio-control agents (Trichoderma asperellum and Bacillus subtilis), plant extracts, and plant oils were tested in vitro. Eleven plant extracts were tested, including Neem, Ginger, Garlic, Moringa, Pungam, Calotropis, Castor, Eucalyptus, Bermuda grass, Nithya kalyani, and Bougainvillea, each with a 10% concentration. Ginger extract showed the highest inhibition (66.34%) compared to the control pathogen. Six plant oils were also tested, including Neem oil, Pungam oil, Groundnut oil, Illuppai oil, Mustard oil, and Castor oil, each with a 5% concentration. Pungam oil showed the highest inhibition (45.56%) among the plant oils. The bio-control agents Trichoderma asperellum and Bacillus subtilis displayed growth inhibition of 45.34% and 37.45%, respectively. From these results, it was concluded that biocontrol agents, plant extracts, and plant oils exhibited significant inhibition of the growth of Alternaria polianthi.

Keywords

Alternaria polianthi, Biological management, Biocontrol agents, Plant extract, plant oils

Conclusion

From this study, leaf spot of tuberose is caused by Alternaria polianthi, which was isolated from infected symptoms and confirmed through morphological examination. The efficacy of different plant extracts, plant oil, and two biocontrol agents was assessed against the pathogen. Ginger extract, pongamia oil, and Trichoderma asperellum effectively inhibited the growth of the pathogen. These products will be tested under pot and field conditions to confirm their ability to manage leaf spot of tuberose.

References

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How to cite this article

P. Mahalakshmi, M. Ayyandurai and P. Mareeswari (2023). Encountering the effects of Leaf Spot (Alternaria polianthi) on Tuberose (Polianthes tuberosa) by Biocontrol agents, Plant extracts, and Plant Oils. Biological Forum – An International Journal, 15(6): 142-147.