THE INFLUENCE OF THE JUVENILE-HORMONE ANALOG (S)-HYDROPRENE ON APROSTOCETUS-HAGENOWII (HYMENOPTERA, EULOPHIDAE), AN OOTHECAL PARASITOID OF THE ORIENTED COCKROACH BLATTA-ORIENTALIS (DICTYOPTERA, BLATTIDAE)

The synthetic juvenile hormone analogue (S)-hydroprene can control pop ulations of the oriental cockroach Blatta orientalis Linnaeus. Eradica tion of B. orientalis infestations, however, can take in excess of two years. In an attempt to reduce the time (S)-hydroprene takes to elimi nate a population of oriental cockroaches, we explored the possibility of using the oothecal endoparasitoid Aprostocetus hagenowii Ratzeburg in combination with (S)-hydroprene. For such a strategy to be success ful, it is important that the parasitoid remains substantially unaffec ted by (S)-hydroprene. When A. hagenowii was exposed to B. orientalis oothecae in the presence of (S)-hydroprene, female parasitoids showed no reduction in their capacity to attack hosts and their fecundity was not compromised. (S)-hydroprene, at dose rates of 18 mg/m(2) and 100 mg/m(2), induced deformity in approximately 12% and 33% respectively o f parasitoids that emerged. No reduction in reproductive viability was seen in morphologically normal R parasitoids. Deformed F-1 parasitoid s, exposed to the higher (S)-hydroprene dose, showed a 71% reduction i n the number of oothecae attacked and a 50% reduction in the number of offspring produced. These results indicate that A. hagenowii could be used in combination with (S)-hydroprene in an integrated pest managem ent programme against B. orientalis.