COMPETITION OF A SPORIDESMIN-PRODUCING PITHOMYCES STRAIN WITH A NONTOXIGENIC PITHOMYCES STRAIN

Sporidesmin, a mycotoxin produced by some strains of Pithomyces charta rum, is responsible for the hepatogenous photosensitisation disease fa cial eczema, which causes severe losses in agricultural revenue in New Zealand. A sporidesmin-producing strain of P. chartarum, isolated in New Zealand, was grown in co-culture with a South African strain that does not produce the mycotoxin. Competition occurred between the two s trains when grown both on agar plates and on dried ryegrass, with a si gnificant decrease in the total amount of sporidesmin produced. Biolog ical control of toxigenic P. chartarum can thus occur under laboratory conditions, raising the possibility of similar control in the field s ituation.