PUB - Publikationen an der Universität Bielefeld

BACKGROUND: Wireworms (Coleoptera: Elateridae) are major insect pests of worldwide relevance. Owing to the progressive phasing-out of chemical insecticides, there is great demand for innovative control options. This study reports on the development of an attract-and-kill co-formulation based on Ca-alginate beads, which release CO2 and contain neem extract as a bioinsecticidal compound. The objectives of this study were to discover: (1) whether neem extract can be immobilized efficiently, (2)whether CO2-releasing Saccharomyces cerevisiae and neem extract are suitable for co-encapsulation, and (3) whether co-encapsulated neem extract affects the attractiveness of CO2-releasing beads towards wireworms. RESULTS: Neem extractwas co-encapsulated togetherwith S. cerevisiae, starch andamyloglucosidase with a high encapsulation efficiency of 98.6% (based onmeasurement of azadirachtin A as themain active ingredient). Even at enhanced concentrations, neemextract allowed growth of S. cerevisiae, and beads containing neem extract exhibited CO2-emission comparable with beads without neem extract. When applied to the soil, the beads established a CO2 gradient of>15 cm. The co-formulation containing neem extract showed no repellent effects and was attractive for wireworms within the first 24 h after exposure. CONCLUSION:Co-encapsulationof S. cerevisiaeandneemextract is a promising approach for the development of attract-and-kill formulations for the control of wireworms. This study offers new options for the application of neem extracts in soil.