Occurrence and management of coconut root (wilt) disease in TamilNadu, India

Coconut root (wilt) disease associated with phytoplasma presence is the most important and devastating disease of coconut plantations in southern India especially in Kerala and Tamil Nadu. A survey was undertaken to evaluate the occurrence of root (wilt) disease in border districts of Kerala and Tamil Nadu during five years from 2010 to 2015. The maximum disease incidence was observed in Tirunelveli (16.77%) followed by Theni (7.83%) districts. Coimbatore district which houses the largest coconut plantations in Tamil Nadu exhibited up to 12.97% of disease incidence in Pollachi north and south blocks between 2012 and 2013. Though several approaches have been developed to manage the disease, there is no effective strategy to prevent it in the coconut palms. A field trial conducted at Manakkadavu village of Anaimalai block in Coimbatore district revealed that the application of fertilizers at recommended dose, along with root treatments with oxytetracycline at 100 mg/100 ml water per palm at monthly intervals effectively reduces the symptoms of root (wilt) disease. However, discontinuation of root treatment and other management practices would result in re-appearance of symptoms after three years due to increased phytoplasma presence.