Recent status and distribution pattern of cotton leaf curl disease in Northwest India: an alarming situation in future cotton cultivation

unknown. A survey was made to study cotton leaf curl disease (CLCuD) incidence in cotton growing areas of Haryana, Punjab and Rajasthan in Northwest (NW) India during the years of 2013 and 2014. The present study revealed higher overall CLCuD incidence of 77.5% with higher overall boll number reduction (BNR) of 36.9% in 2013 compared to incidence of 49.6% with 7.6% BNR in 2014 in Haryana. In Rajasthan the disease incidence of 55.9% and 21.6% BNR in 2013 when compared to 10.8% of incidence and 2.9% BNR in 2014 was recorded. The overall CLCuD incidence and BNR in cotton growing areas of Punjab were more or less similar for both the years of 2013 and 2014, where disease incidence of 54.1% with BNR 14.6% in 2013 and disease incidence 57.8% with BNR of 15.9% in 2014 was recorded. All the 11 Bt-cotton hybrids from the farmer’s fields of Sri Ganganagar and Sirsa districts surveyed were highly susceptible to CLCuD in both the years; showing 100% disease incidence with BNR of 32.3-82.3% in 2013 and 49.2-100% with BNR of 8.7-17.4% in 2014. Infectivity study through whitefly (Bemisia tabaci) and polymerase chain reaction (PCR) of ORF V1 (CP gene) determined that CLCuD in NW India is caused by whitefly transmitted CLCuD-begomoviruses. Sequence analysis of CP gene indicated that at least three CLCuD-begomoviruses variants appeared in this cotton growing region. The increased CLCuD incidence with huge yield loss and occurrence of CLCuD-begomovirus variants reported in the present is an alarming situation for the profitable cultivation of cotton in north India.