Vol. 11, Special Issue 6 (2022)

Author(s):
Sowmiya S, Rajeswari E, Paranidharan V and Anandham R

Abstract:
Cotton is an important economic crop in India and across the world. It is affected by many diseases caused by fungi, bacteria and virus. Among these, bacterial blight incited by Xanthomonas citri pv. malvacearum is the most widespread and destructive disease inflicting yield losses ranging from 10% to 30%. Roving survey was conducted to assess the severity and the distribution of bacterial blight in eight major cotton growing districts of Tamil Nadu during two seasons viz., winter 2021 and summer 2022. The results revealed that the highest bacterial blight incidence of 18.5 PDI (Percent Disease Index) was recorded in Ramanathapuram village of Salem district followed by Kallipalayam village of Coimbatore district in which 15.7 PDI was registered. The least incidence of 2.9 PDI was found in Ramalingapuram village of Virudhunagar district. The mean district incidence of the bacterial blight during the winter and the summer seasons of 2021 and 2022 ranged from 3.5 to 16.0 PDI and 2.6 to 13.8 PDI respectively. The maximum PDI of 16.0 was found in Salem district and the minimum of 3.5 PDI was recorded in Virudhunagar district during winter season 2021. Pin prick inoculation method was proved to be the best method for artificial inoculation studies.