Four decades of research on phytoplasma diseases of palms: A review

Phytoplasmas are important pathogens of hundreds of plant species all over the world. They have been reported to affect not only yield and product quality, but also plants survival. Palms are cultivated in tropical and subtropical areas of the world. Phytoplasmas affecting palms (date palms, oil palms and coconut trees) have received great attention from researchers due to the importance of palms as a main food commodity in different parts of the world. Phytoplasmas result in different symptoms in various palm species, collectively known as lethal yellowing diseases. Several diseases outbreaks have been reported in palms due to phytoplasmas, including the "coconut bud rot" which resulted in extensive yield loss and stopped the commercial production of coconuts in the Caribbean. This review discusses the most common phytoplasma groups affecting palm species as well as their history, distribution and host range. In addition, information is provided about losses due to phytoplasma diseases in palms, potential methods of transmission, the interaction between palms, phytoplasmas and vectors and potential management strategies.