The biological characteistics of strain QZ-200 of curvularia sp.for controlling Digitaria sanguinalis

Factors influencing vegetative growth, conidial germination and sporulation of strain QZ-200 of Curvularia sp. , a biological control agent for crabgrass (Digitaria sanguinalis ), had been primarily studied. SCS (soyflour-cornmeal-su- crose) was the best medium for vegetative growth tested so far. The ranges of temperature and pH for mycelial growth were 10-40℃ and 2-11, the optimum were 28℃ and pH 6 respectively; the fungus grew better in Czapek medium with glucose as carbon source and (NH_4)_2HPO_4 as nitrogen source. The ranges of temperature and pH for conidial germination of strain QZ-200 were 10-45℃ and 2-11, the optimum were 25-30℃ and pH 5-8; under RH 100% or in free water, the percentage of conidial germination was the highest and the germination was stimulated by adding of peptone, beef extract, TW-80, crabgrass extract or rapeseed oil to the media. The range of temperature for sporulation was 15-35℃, the optimum was 28℃; the continuous illumination gave better result than an alternating of light and darkness for 12 hours, and the black fluorescent light was the best illumination for sporulation.