Production of Didymella rabiei Pseudothecia and Dispersal of Ascospores in a Mediterranean Climate.

ABSTRACT Temperature and wetness conditions required for development and maturation of Didymella rabiei pseudothecia were determined in a series of experiments conducted in controlled-environmental conditions. Initial stages of pseudothecium formation occurred at temperatures ranging from 5 to 15°C. Incubation at low temperatures was essential for subsequent pseudothecium maturation. This requirement was satisfied for chickpea stem segments incubated at 5 or 10°C for three consecutive weeks or during periods of 3 or 5 days, separated by periods at higher temperatures. Following the low-temperature requirement, subsequent pseudothecium development was independent of temperature in the range tested (5 to 20°C). Wetness was essential for pseudothecium production: pseudothecia formed and matured on stem segments maintained continuously wet but also on those exposed to periods of three or five wet days, separated by dry periods. The dispersal of D. rabiei ascospores was studied using chickpea plants as living ...