Evaluation of different Botanicals for the Management of Late Blight (Phytophthora infestans) of Potato in Karnataka

Author: Mahaveer N. Shebannavar, Devappa V., Ramachandra R.K., Anjaneya Reddy B. and Sangeetha C.G.

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Abstract

Amongst all the vegetables, potato is one of the most important tuberous crops and is being constrained by many diseases like early blight, late blight, wart, black scurf, powdery scab etc. One of them which becomes endemic in a particular area and brings > 60 % yield loss is late blight of potato. It is caused by Phytophthora infestans, which can affect the crop both qualitatively as well as quantitatively if no early measures are adopted in a short period. Prolonged usage of fungicides has a long-lasting negative impact on bio-diversity with increase in cost of cultivation. With this back ground, totally 20 plant extracts (botanicals) were examined under in-vitro conditions, using three methods viz., water extraction, methanol extraction and ethanol extraction methods. The results revealed that in water extraction method the clove extract was very effective in suppressing mycelial growth of Phytophthora infestans. While in methanol extraction, clove extract, black pepper, thyme, turmeric and pepper mint had shown a very good response to supress the pathogen at all the concentrations tested. But in ethanol extraction method, it was observed that clove and black pepper were the best ones with 100 per cent inhibition for ten days. Among all the methods, ethanol extraction method was found to be the most effective extractant whereas clove and thyme extracts had a good potential anti-fungal property.

Keywords

Botanical extracts, Late blight, Potato, Phytophthora infestans

Conclusion

Late blight of potato is one of the serious fungal diseases which has become very difficult to control even with the continuous use of fungicides creating additional production costs and adverse environmental hazards besides the development of resistance against fungicides. In order to avoid these adverse effects, the importance must be given towards the usage of eco-friendly measures in the form of botanicals. Hence, 20 plant extracts were used using three extraction methods viz., water, ethanol and methanol extraction methods. The results of the water extraction method and tested under in vitro conditions revealed that the extractants from clove was very effective (100 per cent inhibition) in suppressing the mycelial growth of Phytophthora infestans at all the concentrations viz., 5,10 and 15 per cent tested even after 10th day of incubation. While in methanol extraction method, the clove extract has inhibited 100 per cent mycelial growth at all the concentrations tested followed by thyme extract with 94.37 per cent inhibition at 5 per cent concentration, 95.77 per cent at 10 per cent concentration and 98.53 per cent at 15 per cent concentration even after ten days of incubation. In ethanol extraction, clove and thyme extracts had 100 per cent inhibition at all the three concentrations tested even after ten days of incubation. Among the different extraction methods, the ethanol extraction method was found to be effective, while among the plant products used clove and thyme extracts were very effective with 100 per cent inhibition against Phytophthora infestans growth under in-vitro conditions even after ten days of incubation. These products can be further studied under natural conditions to ascertain its field efficacy.

References

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How to cite this article

Mahaveer N. Shebannavar, Devappa V., Ramachandra R.K., Anjaneya Reddy B. and Sangeetha C.G. (2022). Evaluation of different Botanicals for the Management of Late Blight (Phytophthora infestans) of Potato in Karnataka. Biological Forum – An International Journal, 14(4): 1182-1187.