Sugarcane diseases: Diagnostics and management

Sugarcane is a major field crop grown essentially for sugar and other sweeteners in India and in many other tropical and subtropical countries. Recently, it has emerged as a bioenergy crop for producing bioethanol for automobiles. Diseases caused by fungi, bacteria, viruses, phytoplasma and nematodes have become major constraints for sugarcane productivity. In spite of all the efforts of breeding for disease resistant varieties, this crop is becoming more and more prone to many diseases. The disease incidences are increasing at an alarming rate and the yield is falling down every year and sugarcane diseases cause a loss of several billions of dollars across the globe, every season. About 10–15 per cent of the nations sugar produced are lost due to diseases. Among the diseases red rot, smut, wilt and pineapple disease (sett rot) are the important fungal diseases. Bacterial diseases like leaf scald (LSD) and ratoon stunting (RSD) are found to cause considerable yield loss in some states. Also red stripe are known to cause damage in subtropical regions in India. Among the viral diseases, mosaic and yellow leaf (YLD) are the major diseases affecting sugarcane. Besides these, grassy shoot caused by phytoplasmas is also a potential disease, which can cause considerable damage to sugarcane production in all the states. Foliar diseases such as yellow spot, brown spot, brown stripe, eye spot, ring spot, rust etc may cause loss to sugarcane depending on the prevailing environmental conditions. Many promising varieties were removed from cultivation in the past since they succumbed to new pathogenic variants of red rot with more virulence. Also slow build up of many non-fungal diseases in sugarcane causes decline in varietal performance and results in varietal degeneration. In this review, important diseases of sugarcane and their management are briefly described.