In vitro efficacy of fungicides on Uredospore Germination Inhibition of Puccinia graminis tritici

Author: Shipra Sharma, Rashmi D. and S. I. Patel

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Abstract

Wheat is one of the important cereals and is highest produced grain in the world after corn and rice. It is the second most important crop in India next to rice. Like several crops, wheat is also prone to diseases. Among various diseases, wheat stem rust is the main biotic constraint to wheat production and it is important to understand and analyse the disease in terms of pathological and biochemical responses. Systemic fungicides belonging to group of triazole, strobilurin and benzimidazoles exhibited effective mean uredospore germination inhibition in the range of 76.74 to 94.83 per cent. Significantly, the high mean inhibition of 95.33 per cent was recorded in propiconazole, followed by hexaconazole with 92.76 per cent germination inhibition. Least uredospore germination inhibition (76.74) was found in carbendazim. Effective inhibition of combined fungicides was ranged from 83.21 to 96.38 per cent. Nearly complete (99.22 %) inhibition of germination of uredospores was exhibited by azoxystrobin + tebuconazole at highest concentration of 500ppm. It was noticed that carbendazim + mancozeb at 100 ppm performed inferiorly compared to other treatments by recording the least uredospore germination inhibition of 79.85 per cent. Evaluation of various fungicides helps in the determination of suitable chemical for management and overcome fungicidal resistance. Emergence of new races also pose threat to current fungicide in use. Hence rigorous evaluation of combination fungicides help in understanding the efficacy against rust pathogen.

Keywords

Wheat, rust, inhibition, urediospores, fungicides

Conclusion

Propiconazole and hexaconazole were found to be the best performing fungicides in vitro by recording mean germination inhibition of 94.83 and 92.76 per cent. The uredospore germination inhibition was comparatively low (76.74%) in carbendazim. Among the combined fungicides, Azoxystrobin + tebucanazole and tebuconazole + trifloxistrobin proved to be the best fungicides in vitro with mean uredospore germination inhibition of 96.38 and 95.09 per cent. Carbendazim + mancozeb resulted in 83.21 per cent mean uredospore germination inhibition and thereby proved comparatively inferior. A rapid method of quantifying the fungicide effectiveness with detached leaves was developed to study wheat stripe rust, caused by Puccinia striiformis f. sp. tritici. The results revealed that 0.5% water agar containing 75 μg/ml of 6-benzylaminopurine and filter paper worked the best for maintaining wheat leaves. The disease incidences of different concentrations of spore suspension were compared. When the spore concentrations were 5 and 10 mg/ml, the disease incidences had no significant differences at 12 and 15 days after inoculation (P < 0.05). Fungicide treatment tests revealed that there were no significant differences in the efficacies of triadimefon on rust suppression between detached leaves in the culture dishes and direct spray on seedlings (Peng et al., 2020). The spore germination inhibition of Puccinia triticina with different combination of fungicides in laboratory conditions was investigated by Khunt et al. (2019). The relative efficacies of eight different fungicides combination were tested at different concentrations viz., 200, 500 and 1000 ppm. The data indicated that the maximum mean reduction of uredospore germination (84.48%) was found in the treatment of pyraclostrobin 13.3% + epoxyconazole 5% WP followed by tebuconazole 50% + trifloxystrobin 25% WG with 76.34 per cent inhibition. The other fungicide viz., cymoxanil 8% + mancozeb 64% WP (71.90%) was found moderately effective.

References

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How to cite this article

Shipra Sharma, Rashmi D. and S. I. Patel (2023). In vitro efficacy of fungicides on Uredospore Germination Inhibition of Puccinia graminis tritici. Biological Forum – An International Journal, 15(5): 372-376.