Influence of temperature and moisture on growth and sporulation of Botrytis squamosa

Abstract

Growth of Botrytis squamosa in artificial media or autoclavcd onion leaves was favored at temperatures of 15 or 20 °C but was much less at 30 °C or above. Hyphae did not grow in artificial media or autoclaved onion leaf segments below −95 to −100 bars (1 bar = 100 kPa) water potential within 4 days at 20, 25, or 30 °C. Growth was stimulated when water potential was adjusted to −5 to −20 bars compared with higher or lower values. Mycelia of B. squamosa survived air drying in autoclaved leaf segments for 12 days at 20 °C. When colonized dried leaf segments were placed on water agar, sporulation began after 2 days and continued through 6 days. Sporulation from colonized dried leaf segments was abundant at 15 or 20 °C, less at 25 °C, and absent at 35 °C. When subjected to alternate wetting and drying periods, sporulation on colonized dried leaf segments decreased with increasing length of the dry period.