The study of the Mycorrhizal Fungi and Nutrients effect to the Gummosis Disease caused by Phytophtora sp. Pistachio

Pistachio is an important export product in Iran. This product is always damaged by various living and non-living agents. One of the diseases that cause damage to this pistachio tree in most areas of pistachio is gumosis disease caused by Phytophthora drescleri. Various methods have been proposed for the management of this disease such as the use of resistant cultivars, the use of biological control and changing soil environment conditions to make the conditions unfavorable for pathogen control. In this study, it was used the ammonium sulfate, potassium sulfate and triple superphosphate against gum disease. The results showed that the highest rate of growth reduction of pathogenic fungi was related to the concentration of 2500 ppm ammonium sulfate compound (67.16percent). In the greenhouse, the effects of different treatments including mycorrhizal fungi and ammonium sulfate alone and their combination in reducing disease caused by P. drescleri on growth traits such as plant height and leaf area were evaluated. In the other part of the study, the effects of these treatments on physiological traits such as total chlorophyll and antioxidant enzymes activities such as peroxidase, catalase and polyphenol oxidase were investigated. The results showed that treatment with mycorrhizal fungi and ammonium sulfate always had the highest height and leaf area among the treatments, with 25.53 cm2 and 81.19 cm2 respectively compared to healthy control with 82 cm cm, respectively 16.82 and 50.39 cm2). Regarding physiological characters as well as trace elements content, the most frequent treatment was the combination of mycorrhizal fungi and ammonium sulfate in both Bo cultivars for chlorophyll and catalase, peroxidase and polyphenyl oxidase enzymes. In the case of the two cultivars, Sarakhs and Almonds, because Sarakhs was more susceptible to Almonds, were always lower in all studied traits. The results showed that the use of mycorrhizal fungi as well as ammonium sulfate improved plant condition and plant resistance to pathogen. In the first part of the study, it was also shown that some nutrients in addition to the positive effect on the plant have a negative effect on the pathogen.