Efeito da temperatura e umidade do substrato na viabilidade de Sclerotium rolfsii

Abstract

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 58°C. 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 °C. From all temperatures tested, only the lowest (40°C) did not eradicate pathogen sclerotia. Soil treatment at 40°C/30 min. stimulated sclerotia germination as the level of substrate humidity was increased. At temperatures of 52 and 58 °C, and at humidity levels of 5, 6, 9, 11 and 18%, a 30 min. treatment was efficient for eradication of the pathogen. At 48°C, sclerotia eradication reached 80 to 100% for humidity levels of 5 to 18%. S. rolfsii was eradicated with humidity heat.