Institut für ökologische Chemie, Pflanzenanalytik und Vorratsschutz
In the field, after harvest, and before processing and sale, storable plant products must be protected from damage and infestation by harmful organisms. Therefore, stored-product protection is an important part of the value chain. In addition to physical impacts such as heat or moisture, biological factors and especially insects pose the greatest threat. The search for alternative measures against pests in integrated pest management are not only general trend in agriculture, but also in stored-product protection. The use of beneficial arthropods (e.g., parasitoids) and bioactive natural products (semiochemicals) are two biologically-based strategies to control stored-product pests. However, the potential has been exploited only to a limited extent so far. One of the main reasons is the existing efficacy gap compared to chemical pesticides. This is mainly due to the still very limited knowledge about biology and behavior of many parasitoids of stored-product pest insects, the specific role of semiochemicals in the parasitiod’s host search and finally the correct application under storage conditions. In addition, although already described for a large number of storage pests, only a few parasitoid species have been further investigated for their efficacy in biological control and are commercially available.In the present project, existing concepts for the use of parasitoids and semiochemicals will be optimized and an innovative method for combining both strategies will be developed. Ultimately, species-specific pest control will achieve an environmentally compatible and also for human health gentle and sustainable stored-product protection,which is particularly important for organic farming. Overall, this approach could reduce the use of conventional pesticides and thus lower the risk of chemical residues in food/feed and at the same time contribute to climate protection. This approach will be investigated in more detail on the larval parasitoid Cephalonomia waterstoni (Hymenoptera: Bethylidae), which is not yet commercially available. This is a natural antagonist and potential candidate for the control of the rusty grain beetle Cryptolestes ferrugineus (Coleoptera: Laemophloeidae). Cryptolestes ferrugineus is a worldwide pest of stored plant products such as cereals, corn, rice, and dried fruits. In research phase I of the project, adult C. waterstoni will initially be caught on various farms and/or obtained from stocks at other research institutions in order to set up a mass rearing of the parasitoid in the laboratory of Biologische Beratung GmbH. To ensure a sufficient number of test individuals for the upcoming analyses and behavioral tests, a parallel rearing set-up will be established at the JKI. For rearing optimization, studies on biology of the host and the best development parameters for the parasitoid will be carried out by Biologische Beratung GmbH. Odor collection and analysis of host and feeding substrates will be initiated at the JKI. As a stop criterion of the project, it will be verified at the end of research phase I whether a mass rearing of C. waterstoni has been established. In research phase II, chemical analysis (GC-MS) and electrophysiological methods (GC-EAD, EAG) will be used at the JKI to identify the volatile compounds used by the parasitoid to find a host. Subsequently, olfactometer tests will be carried out to study the host-finding behavior of odor-inexperienced C. waterstoni females without additional semiochemicals and with the addition of the attractive compounds. Effective odor lures for attracting C. waterstoni will be developed by analyzing and comparing the evaporation rates of compounds applied to different dispensers. Finally, the effectiveness in host finding and parasitizing pest larvae of odor-inexperienced parasitoids as well as parasitoids trained with (host-) specific volatiles will be determined in semi-field trials with flight cages at JKI. The optimization and expansion of the mass rearing of parasitoids will be continued by Biologische Beratung GmbH in research phase II.The knowledge gained in the laboratory on the efficiency of the parasitoid in biological control and on attractive key compounds can directly feed into the development of a commercial breeding of the new beneficial insect and its practical application in stored-product protection.
Federal Ministry of Food and Agriculture