The influence of the juvenile hormone analogue (S)-hydroprene onAprostocetus hagenowii(Hymenoptera: Eulophidae), an oothecal parasitoid of the oriental cockroachBlatta orientalis(Dictyoptera: Blattidae)

Abstract

AbstractThe synthetic juvenile hormone analogue (S)-hydroprene can control populations of the oriental cockroachBlatta orientalisLinnaeus. Eradication ofB. orientalisinfestations, however, can take in excess of two years. In an attempt to reduce the time (S)-hydroprene takes to eliminate a population of oriental cockroaches, we explored the possibility of using the oothecal endoparasitoidAprostocetus hagenowiiRatzeburg in combination with (S)-hydroprene. For such a strategy to be successful, it is important that the parasitoid remains substantially unaffected by (S)-hydroprene. WhenA. hagenowiiwas exposed toB. orientalisoothecae 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/m2and 100 mg/m2, induced deformity in approximately 12% and 33% respectively of parasitoids that emerged. No reduction in reproductive viability was seen in morphologically normal F1parasitoids. Deformed F1parasitoids, exposed to the higher (S)-hydroprene dose, showed a 71% reduction in the number of oothecae attacked and a 50% reduction in the number of offspring produced. These results indicate thatA. hagenowiicould be used in combination with (S)-hydroprene in an integrated pest management programme againstB. orientalis.