Evaluation of endod (Phytolacca dodecandra L.) extracts against Botrytis fabae, a causative agent of chocolate spot disease of Vicia faba

The use of botanicals to control phytopathogens of crops is an alternative to the use of synthetic fungicides. The objective of this study was to evaluate the in vitro growth inhibitory effect of Phytolacca dodecandra extracts on Botrytis fabae and their in vivo efficacy to control chocolate spot disease of Vicia faba caused by it. Growth inhibitory effects were evaluated by applying different concentrations of aqueous, methanol or ethanol leaf extracts of P. dodecandra, or extraction solvents (control) by agar diffusion method. Disease incidence and severity were evaluated in vivo by spraying leaf extracts of P. dodecandra on V. fabae plant grown in the field soon after the detection of disease symptoms. All solvents' extracts significantly reduced B. fabae mycelial growth compared to control, and growth reduction increased with increasing extract concentration. The aqueous extract performed better than methanol and ethanol. Results of field experiment also showed that disease incidence was reduced by at least two and three-fold when extracts and synthetic fungicides were applied, respectively. Similarly, disease severity was reduced by at least two-fold and six-fold when extracts and synthetic fungicides were applied, respectively. Application of extracts under field conditions also improved yield compared to the control. Hence, extracts of P. dodecandra are potential alternatives to synthetic fungicide to control the negative impacts of B. fabae.