INFLUENCE OF NOSEMA-BORDATI (MICROSPORIDA, NOSEMATIDAE) ON THE BIOLOGICAL CYCLE OF CHILO-PARTELLUS (LEP, PYRALIDAE), A STEM BORER OF CULTIVATED GRAMINAE

The biological cycle of Chilo partellus (Swinhoe) was described on art ificial diet. From egg to adult, it lasted 32 to 49 days with an avera ge of 36.6 days. About 2,000 larvae from the 2nd to the 5th instars we re artificially infected by ingestion with doses of Nosema bordati Gou degnon, varying from 2 x 10(2) to 2 x 10(7) spores per ml. Only 72 sur vived (7.66 %) of these infected larvae. N. bordati, when present in t he larvae, continued to multiply in the resulting pupae. The parasite affected the adults of this Pyralid reducing in a proportion of 5 the productivity of infected females and increasing the production of ster ile eggs in the proportion of 8.