Biocidal Efficacy of Plant Volatiles Obtained from Brassica species Against Fusarium wilt of Eggplant caused by Fusarium oxysporum f.sp. melongenae

Author: V. Govardhan Rao and H.S. Viswanath

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Abstract

Eggplant is the most traditional vegetable crop in India. It is susceptible to a number of diseases that reduce yield and quality. Among them, Fusarium wilt caused by Fusarium oxysporum f.sp. melongenae (FOM) is one of the most important soil borne diseases responsible for yield reduction in India. High doses of chemical fungicides are typically employed to treat this disease, but these chemicals have negative effects on both human and environmental health in addition to making disease-causing organisms more resistant to treatment. So, in the current study, a simple, inexpensive, and environmentally friendly method, i.e., soil incorporation of plant components having volatiles, was used to check the growth of a wilt-causing pathogen by testing the efficacy of plant leaf tissues of six cruciferous/Brassica species both in vitro and in earthen pots under laboratory and polyhouse conditions, respectively. During the in vitro study, mustard leaf tissue exhibited maximum mycelial inhibition (90.15 and 77.65 %) followed by Broccoli leaf tissue (65.50 and 73.86%) after five and seven days of inoculation (DAI) respectively. while radish leaf tissue recorded the least inhibitory effect (31.48% and 11.77 %) at 5 and 7 DAI, respectively. In the pot culture test, a similar trend was observed by increasing the germination percentage and decreasing the pre- and post-emergence seedling mortality in all Brassica leaf tissues tested. However, sinigrin concentrations estimated per 100 g of Brassica leaf and root tissues were correlated with the efficacy of different treatments, viz., mustard (512.00 mg and 38.20 mg), followed by broccoli leaf tissue (36.40 mg and 2.80 mg), cabbage (28.40 mg and 0.1 mg), cauliflower (17.20 mg and 0.1 mg), Knol kohl (2.60 mg and 0.1mg) and lastly radish (less than 0.1 mg in both leaf and root) led to a significant reduction of F. oxysporum f.sp. melongenae populations in pot experiment ranging from 12.83 × 106 CFU in mustard to 3.77 × 106 CFU in radish.

Keywords

Fusarium wilt, eggplant, biocidal volatiles, Isothiocyanates, Glucosinolates

Conclusion

Soil borne plant pathogens are among the major factors limiting the productivity of agro-ecosystems. They are often difficult to control with conventional strategies such as the use of resistant host cultivars and synthetic fungicides. The lack of reliable chemicals, the occurrence of fungicide resistance in pathogens and associated environmental risks, and the breakdown or circumvention of host resistance by pathogen populations are some of the reasons underlying efforts to develop new disease control measures. Over the last decade, the attention for bioactive natural molecules is strongly increased because public opinion considers them as a mild, safe and reliable option to prevent or to fight not only several diseases in humans, but even different plant pathogens, thus limiting the use of synthetic pesticides in agriculture. In the present study among the six Brassica spp. tested, Biocidal volatiles released by Mustard leaf tissue exhibited maximum mycelial growth inhibition (90.15% and 77.65%) followed by Broccoli leaf tissue (65.50% and 73.86%) at 5 DAI and 7 DAI respectively. Similarly, in vitro population of test pathogen was inhibited (3.77 × 106 to 12.83 × 106) because of Sinigrin concentrations (512.00 mg and 38.20 mg in leaf and root tissue of mustard) present.

References

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How to cite this article

V. Govardhan Rao and H.S. Viswanath (2023). Biocidal Efficacy of Plant Volatiles Obtained from Brassica species Against Fusarium wilt of Eggplant caused by Fusarium oxysporum f.sp. melongenae. Biological Forum – An International Journal, 15(4): 775-782.