Coconut is an important plantation crop with many decades of life span ,suffers from numerous diseases incited by fungi ,bacteria, virus, viriod and phytoplasma leads to drastic reduction in yield. Roving survey was conducted in five major coconut growing districts of Tamil Nadu viz., Coimbatore, Tirupur, Theni, Tirunelveli and Kanyakumari districts during 2014-2019 for assessing the incidence of important diseases of coconut .The fungal diseases viz., bud rot, basal stem rot, stem bleeding, leaf blight and leaf spot and phytoplasma disease viz., root (wilt) are the widely prevalent disease in these districts. The highest bud rot incidence of 7. 7% was observed in Pongalliyoor village in Coimbatore district and basal stem rot incidence (35.29%) in Manupatti village, Tirupur district . The prevalence of stem bleeding was found to be sporadic and the high incidence of 12.0 % was observed in Therichanamkoppu village, Kanyakumari district. The highest mean district incidence of bud rot, basal stem rot and stem bleeding was registered in Tirupur district which were 1.40 %, 2.59% and 4.94 % respectively. The severity of leaf blight was more (32.0 PDI) in Thanthoni, village, Tirupur district and the leaf spot (25. 5 PDI) in Kaliapuram village, Coimbatore district and the district mean incidence of leaf blight was highest (20.19 PDI) in Tirupur district and leaf spot (10.1 PDI) in Theni district. The maximum incidence (37.25%) of root (wilt) was noted in Gudalore village, Theni district and the district wise average was high (21.1%) in Theni district. The state average of the surveyed district for bud rot, basal stem rot , stem bleeding, leaf blight, leaf spot and root (wilt) incidence ranged from 0.09-0.60%, 0.44-1.03 % , 0. 1 -1.05% 4.9 -8.52 PDI, 2.55 to 6.55 PDI and 5.6-10.3% respectively.
