h i g h l i g h t s H. hebetor parasitism of MHM remains high one year after release. Releases of H. hebetor in two successive years slightly reduced MHM damage. H. hebetor host feeding contributed additional MHM mortality. Augmentative releases of H. hebetor every two years may be sufficient.

No abstract

The fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), is an insect native to the tropical and subtropical Americas that has recently spread to Africa, where it predominately attacks maize, sorghum and other plant species. Biological control is an environmentally friendly way of combatting the pest and contributes to an integrated pest management approach. In Africa, several trichogrammatid parasitoids and Telenomus remus Nixon (Hymenoptera: Platygastridae) have been found parasitizing eggs of the FAW. In Niger, the egg parasitoids encountered include Trichogrammatoidea sp. (Hymenoptera: Trichogrammatidae) and Telenomus remus Nixon. Parasitism of the FAW eggs by the two egg parasitoids was assessed in the laboratory, followed by field testing on sentinel eggs. In the laboratory, T. remus parasitized on average 78% of FAW eggs, compared to 25% for Trichogrammatoidea sp. Telenomus remus was able to parasitize egg masses that were fully covered with scales, while Trichogrammatoidea sp. parasitized only uncovered egg masses. On-farm releases of T. remus in sorghum fields caused up to 64% of FAW egg parasitism. Parasitized eggs yielded viable progeny, which can contribute to FAW egg parasitism build-up during the cropping season. Our findings lay the groundwork for the use of T. remus in augmentative releases against FAW in Africa.

No abstract

The biopesticide Spinosad controls many insect pests of stored-food products. Laboratory and field trials were carried out to determine the efficacy of this pesticide against the cowpea weevil, Callosobruchus maculatus (F.) (Coleoptera: Bruchidae), the main storage pest of cowpea, Vigna unguiculata, Walp, in West Africa. In the laboratory, Spinosad caused high mortality of adult C. maculatus and decreased the number of eggs laid by females. Spinosad, however, was less toxic in the 24 h treatment to C. maculatus than deltamethrin, an insecticide commonly used in Burkina Faso to control this insect. In "on-farm" experiments, Spinosad was effective in controlling C. maculatus. After 6 mo of storage, the number of insects emerging from cowpeas seeds was reduced by >80% by coating seeds with Spinosad but only by 43% by coating with deltamethrin. Less than 20% of the seeds were perforated in the Spinosad treatment compared with 29% for deltamethrin. Spinosad controlled C. maculatus throughout the 6 mo of cowpea storage whereas deltamethrin failed to control C. maculatus after 3 mo of storage. Spinosad has the potential to be more effective in controlling C. maculatus than deltamethrin.