Yellow leaf disease of sugarcane becoming a threatening disease of sugarcane

Abstract

Yellow leaf disease (YLD) caused by Sugarcane yellow leaf virus (SCYLV) is recorded in almost all the sugarcane growing countries in the world. The disease was observed during 1999 in India for the first time and later its wide spread occurrence throughout country was found. In popular varieties upto 100% disease intensity is noticed. The expression of symptoms under field conditions is influenced to a limited extent by different biotic and abiotic factors. Severe infection of YLD was found to significantly affect cane yield and juice quality in popular varieties. The affected plants recorded lesser photosynthetic activity and reduced mobilization of photosynthates from the leaves to sink, thereby reducing the photosynthetic efficiency. Virus-infected planting materials have been found as the main source of disease introduction in the field and secondary transmission of the disease occurs through aphid vectors to varying extent. RT-PCR assays have been standardized to detect the virus from the suspected sugarcane varieties and tissue culture derived seedlings. Efforts are being made to identify the disease-resistant sources to YLD in sugarcane germplasm and to breed YLD-resistant varieties. Elimination of the virus through meristem culture combined with molecular diagnosis has been demonstrated to eliminate the virus from the infected planting materials and establishment of disease-free nurseries in largescale is to be popularized to sustain sugarcane cultivation in different states