Epidemiology of Non-culturable Phloem-Limited Pathogens of Citrus; Case Study Phytoplasma

Abstract

Iran is one of the countries with an important citrus industry. Iranian citrus production suffers from various diseases such as non-culturable phloem-limited diseases (NCPLDs) that caused historical losses on citrus production. Citrus Tristeza Virus (CTV), Witches’ broom disease of lime (WBDL) and Citrus greening (HLB) are the most important NCPLDs in Iran. These three NCPLDs have been observed one after another on citrus orchards across the country. All three diseases are present on the far south Persian Gulf citrus belt with CTV being limited to the Caspian Sea citrus belt. ‘Candidatus Phytoplasma aurantifolia’ is associated with WBDL in citrus cultivation areas located in the Persian Gulf and neighboring countries. WBDL is limited to a few Middle Eastern countries including Iran and has therefore been largely studied in Iran. This chapter reviews the research that has been conducted on this disease in addition to the current challenges that WBDL poses on citriculture. The similarities between WBDL and two other NCPLDs in Iran are discussed, with focus on the epidemiology of NCPLDs that could help coordinate different practices to effectively manage these diseases.