a microsporidia parasite of cotton leafworm Spodoptera litura was successfully established in Spodoptera frugiperda cell cultures by addition of haemolymph from larvae infected with the microsporidia. The most favourable temperature for growth of Nosema sp. was 25℃
but they failed to develop at 37℃. Light and electron microscopy were used to observe the development of Nosema sp. and showed that nuclei in all stages are in diplokaryon arrangement. A sporont divided into two sporoblasts by binary fissioa. The spore nuclei were situated in posterior half of the spore within 12-13 coiles of the polar tube.