Management of strawberry gray mold disease using some essential oils and molecular identification of pathogen fungus

Abstract

Background Evaluation of preharvest application with some essential oils (EOs) for controlling gray mold disease of strawberry plants was studied. Objective In vitro trails, five EOs, that is, thyme, nerol, citral, methyl anthranilate, and clove oils, were evaluated for their capability to suppress fungal growth of Botrytis cinerea. At the National Center for Biotechnology Information, alignment showed the percentage of identity (100%) of B. cinerea between our isolates and Gene bank isolate. Materials and methods Five EOs were evaluated for their capability to suppress fungal linear growth of B. cinerea. Certain volume of each oil was added to autoclaved potato dextrose agar medium flasks to obtain the proposed concentrations of 00.0, 0.25, 0.5, and 1.0% with 0.1% Tween-80. Molecular identification using the internal transcribed spacer (ITS) region of rRNA Trimmed sequences (ITS 573 bp) was conducted. Results and conclusion B. cinerea isolate no. 3 was identified molecular using the ITS region of rRNA Trimmed sequences (ITS 573 bp) compared with different isolates of B. cinerea. All tested oils significantly reduced linear growth of B. cinerea fungus. Complete inhibition was obtained with concentration of 1.0% with all tested EOs and at 0.5% with thyme, citral, and methyl anthranilate, whereas concentration 0.25% showed moderate effect. Moreover, in vivo trails all tested EOs treatments at concentration of 0.5% significantly reduced disease incidence under natural infection. The most effective treatments are citral, methyl anthranilate, and thyme that reduced the disease incidence by 64.3%, 67.9%, and 67.9% on average at 5°C and 75.8%, 82.3%, and77.4% on average at 20°C, respectively, whereas other treatments showed moderate effect. The same trend was observed with disease severity. Meanwhile, under artificial infection, the highest reduction was obtained with citral, methyl anthranilate, and thyme that reduced the disease incidence by 68.2%, 75.0%, and 68.0% at 5°C and 76.0%, 77.0%, and 78.0% on average at 20°C, respectively. However, other treatments showed moderate effect. The same trend was observed with disease severity. As for fruit quality, all tested treatment had no negative effect on all tested characters of fruit quality. The most effective treatments are citral, methyl anthranilate, and thyme that reduced the decay incidence by 71.0%, 71.0%, and 69.3% and weight loss percentage by 79.4%, 78.2%, and 78.8%, respectively. Also, other treatments showed moderate effect, whereas methyl anthranilate, followed by thyme and clove increased the total soluble solid by 56.9%, 41.4%, and 36.2%, respectively. As for total soluble phenol, the highest increase was obtained with all tested oils. As for, titratable acidity, there are no significant differences between all tested treatments as compared with control fruits.