Abstract] A comparison between deltamethrin and Neem kernel solution treatments on Plutella xylostella "L[# popu! lations was made in the Cotonou peri!urban area[ Diamondback moth populations were 09 times larger in deltamethrin plots\ than in Neem plots after treatment[ The number of marketable cabbages from Neem!treated plots was 0[4 times greater than the number from deltamethrin!treated plots[ There was no apparent e}ect of either treatments on Cotesia plutellae "Kurdjumov# populations\ the only parasitoid of the pest that was present in the area[

A laboratory study was conducted on the relationships between Nosema bordati Goudegnon and Apanteles flavipes (Cameron) when they simultaneously parasitise Chilo partellus (Swinhoe). The results indicate that N. bordati is highly pathogenic to the immature instars of the parasitoid. Lightly infected adults of A. flavipes are able to transmit the Microsporidian.

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 2 na to the 5 ~h instars were artificially infected by ingestion with doses ofNosema bordati Goudegnon, varying from 2 x 102 to 2 x l07 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.