Chapter 3 - Updates on phytoplasma diseases associated with fruit crops in Asia

Abstract

The horticulture industry has experienced tremendous growth in Asia during the past 50 years and has developed into one of the major economic branches of modern agriculture. Asian countries have diverse types of tropical, temperate, and coastal climates, hence blessed with diversity of fruits unique to worldwide. Asia contains nearly 44% of the total fruit-producing area in the world and contributes about 42% to the total world fruit production, with the largest and the second largest fruit producers located in this continent. In fruit crops, phytoplasma diseases are important but fewer studies have been done on this group of pathogens particularly in Asian countries. Thus far, 13 groups of phytoplasmas (16SrI, II, III, IV, V, VI, VII, IX, X, XI, XII, XIV, and XXXII) and 29 subgroups have been reported on 26 major tropical, subtropical, and temperate fruit species in Asia. The major phytoplasma diseases which cause serious economic losses to fruit production in Asia are pome and stone fruits, grapes, jujube, papaya, and citrus crops. The rapid emergence and spread of phytoplasmas are due to the enhancement of the international trade of planting materials and their final products. Losses to the quality and quantity of different fruits due to phytoplasma infection have now been widely reported from all over Asia. This chapter provides the most recent information on phytoplasma diseases and their occurrence, symptomatology, diversity, epidemiology, and management in economically important fruit crops in Asian countries.