Plant Pathology Science

Important Criteria for Identification of the Cercospora Species

Mounes Bakhshi

Bakhshi M. 2018. Important criteria for identification of the Cercospora species. Plant Pathology Science 7(1):1-14.

Species of the genus Cercospora are important plant pathogenic fungi with worldwide distribution. They are often associated with leaf spots, occurring on a wide range of hosts in almost all major families of dicots, most monocot families, and even some gymnosperms and ferns. Different characteristics, such as morphology, toxin production and host specificity were used to distinguish species. New research findings have shown that a polyphasic approach, combining morphological, ecological and phylogenetic species concepts, which are discussed in this article, proved the most effective method to distinguish species of the genus Cercospora. Accurate identification of these plant pathogens is the first step to adopt the appropriate management strategies for their disease control. Therefor, it is recommended that, in order to accurate identification of the species of the genus Cercospora, they should be studied and reviewed on the basis of these criteria.

Sooty Canker of Fruit Trees in Iran

Raana Dastjerdi

Dastjerdi R., Nadi S. and Damyar S. 2018. Sooty canker of fruit trees in Iran. Plant Pathology Science 7(1):15-27.

Neofusicoccum mangiferae is the causal agent of branch wilt, blossom blight, canker and dieback on a variety of fruit trees such as almond, hazelnut, apricot, peach, citrus, grape and apple. Cracking and peeling of thin outer layer of bark and exposing black sooty mass of spores is a characteristic feature of disease. Pathogen causes gradual declining and sometimes complete death of trees. The fungus infects the hosts through wounds, created by pruning, frost damage, drought stress, or bark cracks caused by sunburn and develops under hot and sunny weather in summer. Good sanitation, fertilization of trees, adequate irrigation, appropriate pest control, preventing wounds, and avoiding unnecessary pruning are the methods for disease management.

Root Lesion Nematode Pratylenchus thornei

HABIBALLAH CHAREHGANI

Fatemi E. and Charehgani H. 2018. Root lesion nematode Pratylenchus thornei. Plant Pathology Science 7(1):28-39.

Root lesion nematodes are one of the most important and fatal plant parasites. They often move between soil and host plants roots, during all stages of their life. Root lesion nematodes migrate and feed within the roots, therefore they cause necrotic lesions on the surface and throughout the cortex of infected roots. Their attack to the root can result stunting of plant root system as well as reduction in plants growth and eventually host kill. Different management methods such as the planting of resistant genotypes, crop rotation, fallow periods and use of biological control agents are successfully practiced against these nematodes. In this paper a brief discussion of economic damages, importance, taxonomy, biology and symptoms of Pratylenchus thornei attack and the most efficient management methods are presented.

Olive Quick Decline Syndrome Disease

mansureh keshavarzi

Keshavarzi M. 2018. Olive  quick  decline  syndrome  disease. Plant Pathology Science 7(1):40-50.

Quick Decline Syndrome of Olive caused by Xylella fastidiosa subsp. pauca, is currently spread in some European countries in Mediterranean Sea area and there is a risk of its spread beyond the Middle East. The initial symptom is marginal leaf blight, then fruit drop and shoot dieback appears. Growing multiple suckers and finally death of whole tree are the other symptoms. In addition to olive, almond and oleander are also susceptible to this pathogen. The characteristics, biology, host range, transmission and distribution routes of the causal agent are described. In addition, disease prevention and management methods are proposed here.

Mycoviruses Application in Biocontrol of Fugal Pathogens

AHMAD HOSSEINI

Mohammadi M., Hosseini A., Sedaghati E. and Hosseini S. 2018. Mycoviruses application in biocontrol of fugal pathogens. Plant Pathology Science 7(1):51-62.

Mycoviruses or fungal parasitic viruses have dsDNA, dsRNA or ssRNA genome. Some of these viruses have a restricted host range and can infect certain strains of host species. In contrast, some other viruses have wider host range and can infect different species of a fungal family. In most cases these viruses are transmitted by anastomosis of mycelium. In a phenomenon called hypovirulence, most of these viruses decrease the virulence of their host fungus. Discovery of hypovirulence revealed the biocontrol ability of mycoviruses. In summary, mycoviruses could be implemented as powerful agents for biocontrol of fungal pathogens and induction of resistance in plants.

Sulfur Role in Plant Diseases Management

Kamran Ghasemi

Ghasemi K. 2018. Sulfur role in plant diseases management. Plant Pathology Science 7(1):63-72.

Sulfur (S), as a promoter of plant defense system and fungicidal effect, can have a critical role in organic farming. Presence of sulfuric defense compounds including elemental sulfur, H₂S, glutathione, اسیدیتهytochelatins, secondary metabolites and S-rich proteins are vital under stress conditions. As a soil disinfectant, carbon disulfide is widely used against soil-borne pathogens. This is used for controlling the root and crown rot disease caused by Armillaria. Sulfur fumigation is used against powdery mildew in greenhouse production. Fumigation and application of sulfur pad are methods for controlling the grape and some other fruits rot in storage. Besides, sulfur is effective in control of mites, psyllids, and thrips.