Ratoon stunting disease, caused by the bacterium Leifsonia xyli subsp. xyli (Lxx), is one of the most troublesome diseases of sugarcane worldwide. The absence of characteristic external symptoms makes its diagnosis in the field unreliable, helping Lxx to spread by propagating cuttings from infected plants. Thermotherapy of the stalks is the method most used to control this disease in Brazil. Two combinations of time/temperature are currently recommended: 50°C/2h and 52°C/30min. The present work aimed to improve the 52°C-treatment by using additives in order to control Lxx with no deleterious effect on germination. Results of this study showed that the 50°C/2h treatment completely eliminated the pathogen but reduced stalk germination. Adding HCl (1%/10 min) or CH3COOOH(2%) + SDS(1%)/10min in the water at 52°C resulted in higher percentage of control than the treatment at 52°C/30 min, without causing damage to the stalks.
Leifsonia xyli subsp. xyli; thermotherapy; alternative control
