Research

The portfolio of active substances for plant protection products available in the European Union is currently undergoing massive change. While the number of approved active substances has remained roughly the same in recent years, there has been a shift from chemical active substances to microorganisms and other biological active substances, such as plant extracts and pheromones. The background to this development is the constant adaptation of testing methods to new findings and the state of the art in science, as well as the consideration of additional criteria in the approval of active substances (e.g. endocrine properties). This is also intended to support the goal of a sustainable food system within the framework of the European Commission's ‘Green Deal’.While sufficient alternatives are still available for some of the chemical active substances that are no longer approved, lengthy negotiations on individual active substances in the Standing Committee on Plants, Animals, Food and Feed, as well as experience from agricultural practice, show that some chemical active substances are difficult or impossible to replace. Based on the currently established assessment methods, it is already to be expected that further chemical substances will not be approved. In addition, it can be assumed that further findings regarding possible negative effects on human health and the environment will result in individual active substances and even entire groups of active substances losing their approval in the medium term. For example, the problem areas of per- and polyfluorinated alkyl substances (PFAS), succinate dehydrogenase inhibitors (SDHI) and the increase in resistance in the medical sector due to azole active substances, but the new CLP criteria (Classification, Labelling and Packaging) and adaptations to the Drinking Water Ordinance could also influence the availability of PPP active substances. As part of the project, an assessment will now be carried out, taking into account the currently valid evaluation criteria as well as already known future developments and requirements at European level, to determine which active substances may no longer be available in the medium term. After analysing the potential treatment gaps, possible alternatives will be discussed and evaluated in terms of the state of the art, practicability and effectiveness, relevance for Austrian agriculture and the time horizon for future application and implementation.

The onion thrips Thrips tabaci Lindeman (Thysanoptera: Thripidae), favoured by increasing heat and drought, is a problem pest in summer onion crops in the vegetable growing regions of eastern Austria. A natural antagonist is the predatory thrips Aeolothrips spp. If present regularly and in sufficient numbers, it has the potential to sustainably reduce T. tabaci populations in onions. Habitat management is promising in this context: flower strips with a mix of functionally appropriate flowering plants can make arable land attractive and favourable for Aeolothrips spp.. A prerequisite for the success of this control strategy is the clarification of previously unanswered questions regarding the occurrence, behaviour, population development and predation rate. Identifying the most common species of the genus Aeolothrips and the flowering plant(s) on which these predatory thrips are found is of fundamental importance. The attractiveness of the flowering plants and onion plants infested with T. tabaci to Aeolothrips spp. will be investigated under laboratory conditions, as well as their predation rate on infested onion plants. A field trial comparing population dynamics and development of pest and beneficial in summer onion with specifically designed annual and biennial flowering strips will evaluate the potential of habitat management for biological control of onion thrips.

Soybean production in Europe is continuously increasing. Over the past 15 years, the soybean acreage in Austria has tripled, making it the fourth most cultivated crop in the country. Austrian soybeans are particularly important for human consumption and seed production. In the EU, seed certification is granted only if Diaporthe infestation remains below the legally stipulated threshold of 15%. Infestation with Diaporthe disease complex significantly reduces germination capacity and decreases quality, rendering infected soybeans unsuitable for human consumption. Therefore, the project “Unraveling the Epidemiology of Diaporthe: Survival, Transmission, and Host Dynamics in Austrian Soybean Fields”, aims to investigate the impact of Diaporthe on Austrian soybean production. This issue has gained increasingly importance due to expanding soybean cultivation and more favorable climatic conditions for the pathogen. Although Diaporthe has been under study for a long time, many aspects of its epidemiology remain unsolved. Diaporthe is a fungal complex composed of various species that cause different disease patterns in soybean including Phomopsis seed decay, pod and stem blight, and stem canker. The composition of this complex varies geographically, highlighting the necessity of working with the dominant Diaporthe species in specific regions. Disease development is favored by high humidity, rainfall, and elevated temperatures. With climate change, weather conditions conducive to disease outbreaks are becoming more frequent. The primary objective of this project is to examine the epidemiological aspects of the Diaporthe disease complex by studying the survival stages of Diaporthe species present in Austria. In particular, investigating these species in different soybean organs (stem, pod, seed) and their survival structures will help to assess their significance as the initial inoculum for the following year. Furthermore, this project includes a comprehensive examination of the prevalence of Diaporthe species in other host plants, such as crops in crop rotation or weeds, to evaluate the potential of alternative hosts in increasing Diaporthe infection levels within a region or field. Additionally, the mechanisms of transmission between plants and the spatial-temporal distribution patterns within the environment will be examined to gain better understanding of fungal dispersal. Lastly, the behavior of Diaporthe species within the plant remains unknown due to the long latent period. Therefore, this study will also assess the colonization process of soybeans. The results of this project will provide significant insights into the disease cycle of Diaporthe species in soybean. Investigating the role of other crops and weeds may underscore the need to adapt current crop rotation and other agricultural practices to reduce the available inoculum, especially in light of increasing soybean acreage. This comprehensive approach will deepen our understanding of the disease and pave the way for more effective Diaporthe management and sustainable agricultural practices.