Author:

Abstract:

Aphids constitute one of the most important pest insects worldwide, causing crop damage and yield losses in a wide range of economically important crops. Biological control using natural enemies such as predators and parasitoids has become an important way of controlling insect pests. In particular, Aphidius parasitoids have been shown to be most effective against aphids. However, efficacy of Aphidius parasitoids as biocontrol agents can be seriously hampered by dispersal of parasitoids away from the crop, the presence of hyperparasitoids that parasitize the primary parasitoids, and the lack of carbohydrate-rich food sources. Most parasitoids require nectar or other sugar sources for growth, survival and reproduction during their adult stage. Therefore, additional food sources such as nectar or artificial sugar solutions are increasingly provided. Nonetheless, a major challenge remains to attract and retain the parasitoids in the crop so that they can control the pest insects whenever needed. Recently, it has been shown that specific plant- and insect-associated microbes produce volatile organic compounds (VOCs) that are able to attract natural enemies, which makes them highly promising for the development of innovative tools to support biological pest control. The aim of this research was to develop a parasitoid attracting feeding device based on microbial attractants that provides an optimal sugar solution to Aphidius wasps that leads to increased survival and rapid population build-up of the beneficial insects. To this end, a sugar mixture was developed that enhances longevity and survival of the parasitoids, while having no or negative effects on aphids or hyperparasitoids. Next, a diverse microbial collection was screened for production of highly specific VOCs that attract the parasitoids and not the hyperparasitoids. Finally, a feeding device combining both the most effective sugar solution and the most attractive VOC was developed.