Effect of Temperature and Moisture on Various Aspects of Development, Growth, and Pathogenicity of Thielaviopsis paradoxa from Sugarcane in Puerto Rico

Abstract

It was found that the optimum temperature range for mycelial growth and spore germination of Thielaviopsis paradoxa lies between 28° and 32° C, with the maximum above 36° C. and the minimum below 12° C. Neither mycelial growth nor spore germination was obtained at 8° or at 40° C. Pathogenicity of T. paradoxa to sugarcane variety P.R. 1059 was favored by temperatures between 28° and 32° C. No infection of sugarcane by this fungus occurred at 8° or at 40° C. The highest rate of infection of sugarcane by T. paradoxa was obtained at the lowest soil moisture with a maximum temperature up to 32° C. It thus appears that low soil moisture has a profound effect on rate of infection during summer months in Puerto Rico.