Identification of the Fungal pathogens agents of postbloom Fruit drop on citrus in the Northern Iran

• Main Authors: Mohammad A`liyan, Yaqub, Taheri, Hossein, Sheykh Eshkevari, A`li Reza, Hayat Bakhsh
• Format: Publication
• Language: Persian
• Published: Ramsar (Iran) Iran Citrus Research Institute 2008
• Subjects: AGENT PATHOGENE; ALTERNARIA; CAIDA PREMATURA DE FRUTOS; CHUTE DE FRUIT; CITRUS; COLLETOTRICHUM; ENFERMEDADES DE LAS PLANTAS; ENFERMEDADES FUNGOSAS; FRUIT DROP; FUNGAL DISEASES; IRAN ISLAMIC REPUBLIC; IRAN REPUBLICA ISLAMICA; IRAN REPUBLIQUE ISLAMIQUE; MALADIE DES PLANTES; MALADIE FONGIQUE; Mazandaran ( Province ); ORGANISMOS PATOGENOS; PATHOGENS; PLANT DISEASES; Thomson

At present, Planting of commercial cultivars specially is Thomson navel orange is increasing. One of the problems of this citrus cultivar Flower and fruit drop after blooming. In order to study the reasons of this phenomenon, an experiment was carried out in Mazandaran province during 2004-2007. The samples of brown flowers with brown spot and dropped fruitlets were collected from citrus orchards and transferred to laboratory. After washing the flowers and fruitlets with distilled water and 70% ethanol, They were cultured on PDA medium. Then, the grown fungus agents were isolated and purified. More than 100 isolates of fungi including Colletotrichum and Alternaria genus were isolated. More than 80% of them, belonged to Collecotrichum genus. To confirm the disease incidence by isolaes, the stems end of Thomson navel and local oranges were inoculated with fungus disk, and it changed the green color of peel to yellow. On the basis of color and morphological characteristics of colony, conidium specific features, presence of satae appressorium form, optimal temperature of growth and by virtue of valid references, The fungus was identified. as C.acutatum This is the first report of involved fungus agent in relation to Thomson navel orange flowers and fruitlets drop after blooming in north of Iran.