Infectivity of resting spores of Massospora cicadina (Entomophthorales: Entomophthoraceae), an entomopathogenic fungus of periodical cicadas (Magicicada spp.) (Homoptera: Cicadidae).

Massospora cicadina Peck is a fungal pathogen of 13- and 17-year periodical cicadas (Magicicada spp.). In northwest Arkansas, during the spring 1998 emergence of the 13-year periodical cicada, Magicicada tredecassini (Brood XIX), <1% of emerging cicadas were infected with the conidial stage of M. cicadina, similar to data collected from the same population in 1985. However, in northwest Arkansas plots treated with M. cicadina resting spores collected from infected 17-year Magicicada septendecim cicadas (Brood IV) in 1997 from southern Iowa, 10 months prior to the 1998 emergence in Arkansas, conidial stage infections of M. cicadina in 13-year Arkansas M. tredecassini cicadas increased significantly to 10.6% (7.9% in males and 2.6% in females). These data suggest that M. cicadina resting spores do not require a dormancy of 13 or 17 years between cicada emergences. Instead M. cicadina resting spores appear to be capable of germinating and infecting periodical cicadas after less than 1 year. In addition, M. cicadina resting spores derived from one species (17-year M. septendecim cicadas) were infective for a second species (13-year M. tredecassini cicadas). A mean of 1.4 x 10(6)(SE = 1.8 x 10(5)) mature resting spores were produced per infected male M. septendecim.