Sugarcane white leaf phytoplasma (white leaf of sugarcane).

Losses due to sugarcane white leaf (SCWL) phytoplasma vary greatly depending on the susceptibility of the clones, the weather and other environmental conditions influencing sugarcane growth. In Taiwan, over 60 hectares of sugarcane were abandoned due to both high incidence and severity of SCWL disease whereas incidence of more than 10% occurred in 700 hectares. Also, crop losses of 33 and 74%, as well as a decrease of 30% in the sugar content in infected sugarcane plants compared to healthy ones, were recorded (Rishi and Chen, 1989). In Sri Lanka, the incidence of SCWL disease in some sugarcane-growing areas has reached 50-84%, where the yield and quality of infected plants were greatly affected (Chandrasene et al., 2003). In SCWL-affected sugarcane plants, the total chlorophyll content was reduced by 90% while the respiratory rate increased significantly (Chen and Chen, 1974). Affected plants usually die soon after the appearance of the first symptoms. SCWL is one of the most destructive diseases of sugarcane in Thailand (Wongkaew and Fletcher, 2004; Hanboonsong et al., 2006).