Integrated Treatments between Some Essential Oils and Chitosan for Controlling Gray Mold Disease of Bell Pepper Fruits during Storage

Gray mold disease caused by Botrytis cinerea is the most sever diseases attacking pepper fruits. Four purified isolates of Botrytis cinerea were tested for their pathogenic ability to pepper fruits. The most sever isolate is  Botrytis cinerea  no. 3 which caused disease incidence by 90.0, 35.0 & 40.0 % and disease severity by 74.0, 30.0 and 15.0 % for green, red and yellow fruits respectively. The highly pathogenic isolate of Botrytis cinerea no.3 causing gray mold of pepper fruits, was identified using molecular biology and used in the following experiments. In vitro experiments, five essential oils, i.e. thyme, citral, lemongrass, methyl anthranilate and camphor at concentrations of .0, 0.25, 0.5 and 1.0 % were evaluated for their capability to suppress fungal growth and spore germination of Botrytis cinerea.  Results demonstrated that complete suppression of mycelial growth and spore germination was achieved with concentration of 0.5 and 1.0 % of all tested essential oils except that Camphor. Also chitosan at concentration of 6.0 g/L caused complete suppression of mycelial growth and spore germination of Botrytis cinerea. In vivo experiments, essential oils and chitosan were tested alone or in combination with chitosan for controlling gray mold of bell pepper (cvs. Khayrat (green), Antonio (red) and Cleopatra (yellow). The most effective treatments are combination between thyme or citral with chitosan which significantly reduced disease incidence and disease severity. Meanwhile, single treatments showed moderate effect.