Incidence, Intensity and Symptomatology of Mid Whorl Yellowing Disease of Coconut in Southern Kerala, India

Mid whorl yellowing disease (MWYD) of coconut, a disease of an unknown etiology, has caused severe damage to coconut cultivation in southern tracts of Kerala, India. A periodic and purposive roving survey was conducted from 2021 to 2024, over four southern districts of AEU 9 (South central laterites), to assess the incidence and intensity of MWYD on the natural incidence. The average disease incidence and intensity of MWYD in southern Kerala was 1.05 and 0.51 respectively. The disease incidence and intensity of MWY showed a decreasing trend moving northward, from Thiruvananthapuram (1.33% and 0.79%) to Kottayam (0.29% and 0.13%). The MWYD showed symptoms like abnormal nut fall, inflorescence necrosis, yellowing of leaves, especially the middle whorls, and finally death of the palm (telephone pole-like) symptoms. The present study is one of the first comprehensive efforts to detail the symptomatology and assess the incidence and intensity of MWYD of coconut in Kerala.