Dimorphism in Ceratocystis minor var. barrasii.

Ceratocystis minor var. barrasii, a fungus associated with the southern pine beetle, Dendroctonus frontalis, exhibits dimorphism which is influenced by the concentration of both carbon dioxide and phosphate. The mycelium produces blastospores from the tips and sides of its hyphae when the concentration of carbon dioxide is high, and these blastospores germinate if the concentration of phosphate is above about 10(-2) mM, whereas below this concentration they bud.