Development and evaluation of eco‐friendly carvacrol nanoemulsion as a sustainable biopesticide against bacterial leaf blight of cluster bean

Abstract

BACKGROUNDThe study on plant antibacterial components (carvacrol) has recently become a hot topic in modern farming. Carvacrol industrial applications are restricted by their physicochemical instability and partial solubility in water. In the present study, an ultrasonic emulsification method was used to prepare carvacrol nanoemulsion (CAR‐NE) employing nonionic surfactants. The CAR‐NE was characterized using a dynamic light scattering (DLS) instrument and TEM. The goal of this work was nanoencapsulation of carvacrol to improve its aqueous solubility and preservation of encapsulated compound against climatic conditions. Another aim of the present study was the evaluation of the growth‐promoting effects and antibacterial potential of CAR‐NE against bacterial leaf blight of cluster bean.RESULTSCAR‐NE had shown hydrodynamic diameter, zeta potential, and polydispersity index (PDI) of 43.88 ± 4.30 nm, ‐47.8 ± 0.23 mV, and 0.246 ± 0.04 respectively. The spherical shape morphology of CAR‐NE is confirmed by TEM imaging. Minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC) of the CAR‐NE were 20μL/mL and 160μL/mL respectively against Xanthomonas axonopodis pv. Cyamopsidis. Additionally, the antibacterial potential of CAR‐NE was evaluated for controlling bacterial blight of cluster bean in fields. Disease severity in the negative control plants (water) was 84%, but the disease severity in the CAR‐NE (160 μL/mL) was remarkable (14%) which was nearly the same as the positive control (streptomycin sulphate).CONCLUSIONThe shelf‐life of CAR‐NE was two months at room temperature without any appreciable changes in hydrodynamic diameter and zeta potential. Consequently, plants treated with CAR‐NE (160μL/mL) showed substantial improvement in plant growth.This article is protected by copyright. All rights reserved.