Efficacy of Azadirachta indica and Punica granatum Extracts in the Control of Cuminum cyminum Wilt Disease Caused by Fusarium oxysporum f. sp. cumini

Abstract

Punica granatum and Azadirachta indica are plants rich in phytochemicals, which directly contribute to antioxidant activity. The aim of this study was to test A. indica and P. granatum against Fusarium oxysporum f. sp. cumini (Foc), the causal pathogen of Fusarium wilt in cumin plants, in vivo and in vitro. After screening different concentrations of both plants, three concentrations (250, 500, and 1000 µg·mL−1) of P. granatum and A. indica were selected to study their effectiveness against Fusarium wilt in cumin plants. The in vitro study showed that both extracts have the ability to reduce mycelium growth of the pathogen with different degrees of efficacy, but less than the positive control. Under greenhouse conditions, all treatments of cumin plants significantly reduced Fusarium wilt compared to the infected control. The most effective concentration for P. granatum was 1000 µg·mL−1. The use of both extracts significantly increased the fresh and dry weight of cumin plants (g plant−1) compared to infected plants. Total phenols and flavonoids increased in inoculated cumin plants after treatment with both extracts. The results revealed that both extracts are rich in phytochemicals and possess potent in vitro antioxidant activity. Both are rich in carbohydrates, saponins, amino acids, proteins, alkaloids, and terpenoids. In conclusion, the application of methanolic extracts of P. granatum and A. indica can provide an alternative to chemical fungicides to mitigate the Fusarium wilt of cumin and, therefore, future studies should focus on the study of both extracts on different pathogens, as well their ability to reduce disease under field conditions.