The Sugarcane yellow leaf virus (ScYLV), a Polerovirus, Luteoviridae, is an important risk to sugarcane production worldwide because it causes Yellow Leaf Disease (YLD). In severe instances, YLD reduces cane productivity by up to 50 percent and juice yield by 40 to 50 percent. In India, YLD was identified for the first time in the late 1990s, and by 2005, it had become an epidemic in many states.
ScYLV and other viruses and bacteria that infect sugarcane are responsible for varietal degeneration, which reduces the yield potential of subsequent vegetative generations or ratoons. The virus spreads to the field via infected setts. The sugarcane aphid, Melanaphis sacchari, is the insect vector that transmits the virus between plants in the field. It is necessary to implement effective management strategies, such as chemical, biological, natural, and organic control measures, to reduce the impact of YLD on sugarcane production.
Yellow Leaf Disease Management in Sugarcane
The Causal Organisms of Yellow Leaf Disease Disease
Yellow Leaf Disease (YLD) is caused by the Sugarcane yellow leaf virus (ScYLV), a member of the family Luteoviridae. The virus is transmitted by aphids, specifically Melanaphis sacchari and Rhopalosiphum maidis, in a semi-persistent manner. Once the virus enters the plant, it localizes within the phloem cells, resulting in systemic accumulation of the virus at a high titer, ultimately reducing the vigor of the subsequent vegetative generations or ratoons.
The Disease Cycle of Yellow Leaf Disease Disease
Yellow Leaf Disease (YLD) in sugarcane is predominantly transmitted by aphids, specifically Melanaphis sacchari and Rhopalosiphum maximum, via the Sugarcane yellow leaf virus (ScYLV). Additionally, the virus can be transmitted via infected seed cane. Conditions of dry weather begin in October and continue until harvest in March.
Causes/conditions Favorable for Yellow Leaf Disease Disease in the Field
Yellow Leaf Disease (YLD) in sugarcane is transmitted predominantly through infected seed canes and not by mechanical methods. Other susceptible commodities include wheat, barley, sorghum, and oats, but they are only affected when sugarcane is grown nearby. The disease is most apparent in mature cane during arid weather conditions up until the end of harvest. YLD can cause significant yield losses in sugarcane plantations.
Symptoms of Yellow Leaf Disease Disease
- Yellowing of the midrib and adjacent laminar region, followed by midrib withering, in the top three to five leaves.
- Reddish discoloration may also be observed, and, in extreme cases, spindle and leaf dehydration.
- From Octo