INVITRO AND INVIVO GERMINATION OF NOSEMA-LOCUSTAE (MICROSPORA, NOSEMATIDAE) SPORES

Spores of Nosema locustae (E. U. Canning, Parasitology, 43, 287-290, 1953) were induced to germinate in vitro by a two-step procedure. Spores were first activated by drying in air, dehydrated in hyperosmotic solutions of sucrose or polyethylene glycol 400 (PEG), or by extended treatments in low concentrations of PEG. Germination occurred after transfer of the activated spores to an alkaline salt solution, with a pH optimum of 9.0-10.0. Percentage germination in vitro varied from 2 to 50% among different production batches of spores. Germination in the midgut of Melanoplus sanguinipes was consistently near 50% in all batches and dehydration prior to ingestion was not necessary. The in vitro germination stimulus described here is probably not the physiologically normal one. © 1990.