کنترل بیولوژیکی بیماری کپک سبز مرکبات با استفاده از مخمرهای رورست

Green mold (Penicillium digitatum) is one of the most important diseases of citrus fruits during the postharvest and storage stages, which causes significant damage if not properly managed. In recent years, this pathogen has been controlled by the use of chemical fungicides. In order to reduce fungicide consumption and eliminate toxic residues, it is necessary to use other management methods. Use of microbial agents in biological control is one of these methods. Based on previous reports on the ability of yeasts to inhibit pathogens, the ability of native isolates to inhibit pathogen that cause green mold has been investigated. For this study, citrus fruit and leaf samples were gathered from various areas in Mazandaran province. Yeast colonies were then isolated and purified in the lab by using malt agar medium. Due to the large number of isolates, representatives of isolates were selected based on their phenotypic characteristics (shape, color and margin of the colony, physiological characteristics). The biocontrol test was carried out on the fruit with 40 yeast isolates was done in the form of completely random statistival design with 3 replications and 20 fruits in each replication and 3 wells for each fruit separately. At first, 20 µl of yeast suspension with a concentration of 108 cells/ml in sterile water was placed on the wounds created on the fruits and after 8 hours keep at room temperature, the pathogen was sprayed on the fruit at a concentration of 104 cells/ml. The fruits were kept 6 days in storage conditions with more than 90% humidity.The efficiency of yeasts was evaluated based on the control of the occurrence of disease symotoms on the fruit. The results showed that some of yeasts isolates have a good ability with the sequencing of D1-D2 LSU region showed that selected isolates have the highest level similarity to Candida membranifaciens, Rhodotorula mucilaginosa, Pichia kluyveri, Hanseniaspora occidentalis, H. uvarum species which respectively 86%, 73%, 70%, 66% and 98% cause the containment and control of the green mold pathogen in storage conditions.