Plant Pathology Science

Introduction: Citrus bacterial canker caused by Xanthomonas citri subsp. citri is an economically important disease in many tropical and subtropical countries. Several pathotypes of this pathogen have been described which, in addition to certain genotypic features, are distinguished above all by their geographical origin and their host range. Citrus bacterial canker disease is wide spread in Iran and a major threat to the production of Mexican lime (Citrus aurantifolia). Therefore, management of citrus canker is inevitable in citrus growing areas where citrus canker has been established. Application of copper-based bactericides is a standard control measure for management of citrus canker worldwide. Therefore, their long-term use leads to the development of resistant isolates. Plant extracts and essential oils with an antimicrobial effect have become particularly important as an environmentally friendly method for the treatment of plant diseases. Many researchers have recently focused on studying plant extracts and essential oils that contain antimicrobial compounds. Material and Methods: The present study was carried out on the antibacterial effect of ‌Common yarrow (Achillea millefolium), Ginger (Zingiber offcinale), Golden marguerite (Anthemis tinctoria), Fennel (Foeniculum vulgare), Common sage (Salvia officinalis), Gum tragacanth (Astaragalus gossypinus), Summer savory (Satureja hortensis) and True cardamom (Elettaria cardamomum) against two pathotype of Xanthomonas citri subsp. citri under laboratory and greenhouse conditions. Results: All essential oils have an inhibitory effect on multiplication of Xanthomonas citri subsp. citri. The antibacterial test results showed that the essential oils of Ginger and True cardamom strongly inhibited the growth of Xanthomonas citri subsp. citri pathotype, especially the pathotype A*, whereas other essential oils showed moderate to weak activities. Conclusion: The essential oils of these eight plants, especially ginger and cardamom, have good potential for the management of citrus bacterial canker.

Hazelnut tree has natural habitats in northwestern Iran in the forests of Ardabil and Gilan provinces. Decline disease is a threatening agent of hazelnut trees in these areas. Symptoms of the disease include weakness, reduced growth, leaf fall and dieback of the branches, branch and trunk canker and root rot that eventually lead to the gradual death or decline of the tree. In Iran the fungi cause hazelnut decline disease, Diaporthe amygdali, and Cytospora fuckelii as canker and Fusarium semitectum, F. lateritium, F. anthophilum and Armillaria mellea as root rot causative agents. This article describes symptoms of hazelnut decline in Iran, pathogenic fungi and management strategies.

Khezri  M, Allahyari Igdir S, Aghazadeh Soureh Z (2021) Tomato bacterial diseases in West Azerbaijan province of Iran. Plant Pathology Science 10(1):86-96. Doi: 10.2982/PPS.10.1.86.

Introduction: Tomato is one of the most important and most widely consumed vegetable in the world. Tomato also is one of the most important products in West Azerbaijan Province of Iran, which plays an important role in the province's agricultural economy. Accurate bacterial disease diagnosis is the first and most important step in designation methods of disease management. Materials and Methods: Tomato farms in the suburbs of the province cities were visited and diseased plants were sampled. Bacteria were isolated and purified from patient tissues and identified based on phenotypic and molecular characteristics. The bacterial pathogenicity test was performed according to Koch principles. Results: Tomato bacterial pathogens in this province include Clavibacter michiganensis subsp. michiganensis, Xanthomonas vesicatoria, Pseudomonas syringae pv. tomato, P. syringae pv. syringae and Dickya chrysanthemi, agents of bacterial canker,  bacterial spot, bacterial speck,  syringe leaf spot and soft stem rot. Disease symptoms, phenotypic and molecular properties of pathogenic bacteria, previous reports on these bacteria from Iran and their distribution in different regions of West Azerbaijan Province are presented. Conclusion: These bacteria, with the exception of the tomato bacterial canker agent, are reported for the first time from West Azerbaijan province.