Survivability of Nosema locustae (Microsporida: Nosematidae) spores stored at different temperatures and exposed to weather conditions

The survivability of Nosema locustae (Canning) spores, a microsporidian pathogen of locusts and grasshoppers was verified when stored at different temperatures and exposed to weather conditions in the field. The survivability of spores stored in water was 15.1% under sunlight, 27.6% at 40 degreesC under the shade and 33.8% inside at room temperature after 12 days. whereas at 25,10 and - 10 degreesC, it was 80.5, 97.0 and 99.4%, respectively. In the field during monsoon, the survivability of spores sprayed on the plants was 90% after 60 h at temperature between 25 and 31.1 degreesC and relative humidity ranging from 70 to 95%, while in summer, it was 56.4% at temperature between 42.6 and 43.8 degreesC and relative humidity from 18 to 21%. The results suggest that direct sunlight and high temperatures play major role in inactivation of the spores during storage and in field conditions.