Production and Germination of Primary Conidia of Neozygites floridana (Zygomycetes: Entomophthorales) under Constant Temperatures, Humidities, and Photoperiods

The production and germination of primary conidia of Neozygites floridana as affected by temperature, humidity, and photoperiod was studied in the laboratory. All tested factors significantly affected the two processes studied. Production increased with increasing temperature between 13 and 23°C, with means of 35.5 and 55.4 conidia, respectively, discharged from each mummified mite cadaver. No conidia were produced at 28 or 33°C. Conidial production dropped significantly from 96.1/mummy in a moisture-saturated environment [saturation deficit (SD) 0] to 33.9/mummy at SD 0.2. Very few conidia were produced at SD 0.7 (0.6/mummy) and none at SD 1.2. Significantly fewer conidia were produced under continuous light (11.2/mummy) than under continuous darkness (40.1/mummy) or 12L:12D (46.7/mummy) photoperiods. Between 82 and 100% of the conidia produced under 12L:12D photoperiod were released in the dark phase. Germination of primary conidia started within 2 hr and increased with decreasing temperature between 13 and 28°C. Percentage germination of 20.1% at 13°C and 17.6% at 18°C was significantly higher than 11.2% at 28°C. There was no germination at 33°C. High humidities (>95%) were necessary to effect germination. Germination at SD 0 (27.2%) and 0.2 (23.4%) was significantly higher than at SD 0.7 (0.4%), where germination began after 6 hr and was observed only at 13, 18, and 23°C. No germination was observed at SD 1.2. There was no germination among conidia maintained under continuous light.