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 artificial diet. From egg to adult, it lasted 32 to 49 days with an average of 36.6 days. About 2,000 larvae from the 2nd to the 5th instars were artificially infected by ingestion with doses of Nosema bordati Goudegnon, varying from 2 x 10(2) to 2 x 10(7) spores per ml. Only 72 survived (7.66 %) of these infected larvae. N. bordati, when present in the 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 sterile eggs in the proportion of 8.