Thermal eradication of Sclerotium rolfsii in vitro was evaluated under different substrate temperatures and humidity. Humidity levels of 5, 6, 9 and 11% (equivalent to -5, -3, -1 and -1/3 Bar) and 0 and 18% were tested. Temperatures tested were 40, 48, 52 and 58ºC. After substrate treatment, germination in saline BDA medium was evaluated. At 0% humidity, the temperature was not efficient in sclerotia eradication. For all other values of humidity tested, sclerotia were eradicated in temperatures over 52 ºC. From all temperatures tested, only the lowest (40ºC) did not eradicate pathogen sclerotia. Soil treatment at 40ºC/30 min. stimulated sclerotia germination as the level of substrate humidity was increased. At temperatures of 52 and 58 ºC, and at humidity levels of 5, 6, 9, 11 and 18%, a 30 min. treatment was efficient for eradication of the pathogen. At 48ºC, sclerotia eradication reached 80 to 100% for humidity levels of 5 to 18%. S. rolfsii was eradicated with humidity heat.
sclerotia; soil solarization; eradication