INFECTIVITY AND TERATOGENICITY OF BEAUVERIA-BASSIANA IN MENIDIA-BERYLLINA EMBRYOS

Developing embryos of the inland silverside fish, Menidia beryllina, w ere exposed to conidiospores of the insect pathogenic fungus, Beauveri a bassiana, that possessed activity against the migratory grasshopper, Melanoplus sanguinipes. Various adverse;effects were observed in Meni dia beryllina embryos and larvae. They included rupture of the chorion , embryo death, developmental defects (vertebral abnormalities) in the embryo or hatched larvae, and fungal infections on the mandibles of l arvae. Although there was little evidence of a definitive dose-respons e trend based on densities of viable conidiospores, statistically sign ificant (p less than or equal to 0.01) responses were observed in test s in which conidiospore densities were as low as 7.1 x 10(3)/ml and as high as 1.3 x 10(6)/ml. Viable spores were required for adverse effec ts to occur; heat-killed spores failed to cause significant adverse ef fects.