Management of Leaf Spot and Flower Blight (Alternaria tagetica) Disease of Marigold

Author: Vakul Sood, A.K. Singh, Riya and Ritvik Katoch

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Abstract

The fungal pathogen Alternaria tagetica responsible for Alternaria leaf spot and flower blight, poses a significant threat to marigold production, potentially leading to a substantial 50-60 per cent decrease in yield. This study investigated the efficacy of various fungicides and botanicals against A. tagetica. In vitro bioassays were conducted for four fungicides—Azoxystrobin, carbendazim, mancozeb, and copper oxychloride—utilizing different concentrations: 25, 50, 75 ppm for systemic fungicides and 250, 500, 750 ppm for non-systemic fungicides. Additionally, four botanicals—Neem (Azadirachta indica), Darek (Azadirachta melia), Bhang (Cannabis sativa), and Datura (Datura metel)—were tested at concentrations of 10, 20 and 30 per cent. Remarkably, all fungicides and botanicals exhibited significant inhibition of mycelial growth even at the lowest concentrations. In the category of systemic fungicides, Azoxystrobin stood out at 75 ppm resulting in a remarkable 59.81 per cent mycelial inhibition. Among non-systemic fungicides, Mancozeb displayed superior efficacy at 750 ppm achieving a notable 73.89 per cent mycelial inhibition over the control. Neem, among the botanicals tested, proved most effective at 30 per cent concentration, inducing a substantial 81.56 per cent mycelial inhibition. Field trials further validated the effectiveness of these agents in managing Alternaria leaf spot and flower blight disease. Azoxystrobin, at 0.1 per cent concentration, emerged as the most effective, followed closely by Mancozeb resulting in 64.93 and 53.25 per cent disease reduction, respectively, surpassing other treatments

Keywords

Leaf spot, systemic, non-systemic, fungicides, botanicals

Conclusion

In conclusion, the study underscores the economic significance of Alternaria leaf spot and flower blight caused by Alternaria tagetica in marigold production. The in-vitro evaluation of four fungicides and four botanicals revealed substantial inhibition of A. tagetica mycelial growth, even at minimal concentrations. Notably, Azoxystrobin at 75ppm emerged as the most effective systemic fungicide, while Mancozeb at 750ppm stood out among non-systemic fungicides. Neem exhibited remarkable efficacy at 30 per cent concentration among the botanicals. Field trials confirmed the practical utility of Azoxystrobin at 0.1 per cent, surpassing other treatments, with Mancozeb following closely, demonstrating promising disease reduction in real-world conditions at 64.93 and 53.25 per cent, respectively

References

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How to cite this article

Vakul Sood, A.K. Singh, Riya and Ritvik Katoch (2024). Management of Leaf Spot and Flower Blight (Alternaria tagetica) Disease of Marigold. Biological Forum – An International Journal, 16(7): 117-122.