Germination of resting spores of the grasshopper (Orthoptera: Acrididae) pathogen, Entomophaga grylli (Zygomycetes: Entomophthorales), pathotype 2, in selected environments

Resting spores of Entomophaga grylli (Fresenius) Batko, Pathotype 2, a fungal pathogen of grasshoppers, were incubated at combinations of five temperatures (16, 19, 22, 25, and 28 degrees C) and six photophases (0, 4, 8, 12, 16, and 24 h/d). Temperature and photoperiod had significant effects on germination and a temperature-photoperiod interaction was also indicated. Germinated resting spores were found 3 d postincubation at 28, 25, and 22 degrees C. The percentae of germinated spores increased with increased exposure to light and with increased temperatures up to 25 degrees C but appeared to decrease at 28 degrees C. At 25 degrees C and photophases of 12, 16, and 24 h/d, the percentage of germinated resting spores increased more rapidly and attained a higher maximum than spores incubated at other temperature-photophase combinations. Effects of different gaseous environments on resting spores were determined at 25 degrees C and a 16 h/d photophase. The greatest percentage of germinated spores was found in an aerobic environment. The percentage of germinated spores decreased in a microaerophilic environment, and spores in an anaerobic environment did not germinate.