Waste production is becoming a major challenge that requires more effective management strategies. A large proportion of the world’s waste is organic waste, including animal manure, crop residues, food processing waste, municipal sewage sludge and waste from households and some industries. Possible uses of organic waste include its use as fertiliser and soil amendment in agriculture. One of the options for recycling organic waste to produce fertilisers that can be added to the soil is composting, the performance of which depends on several factors such as substrate, moisture, temperature and aeration. The nutrient-rich end products of the composting process can be liquid (compost tea) or solid (compost). In addition, there is a growing interest in the production of insects for food and feed from organic waste as a contribution to the transition to a circular agriculture. The production of insects results in a residue consisting of feed residues in combination with insect faeces and moulted cuticles. This insect frass can be used to restore the natural cycle and promote crop production. However, the organic waste used for composting or as insect food may initially be infested with various types of pathogens. Therefore, heat treatment of fertilisers, which should comply with the relevant standard, is necessary to eliminate most of these pathogens. Some pathogens, including some plant viruses and viroids, are highly heat tolerant and it is feared that they can survive such treatment and consequently lead to infection of the newly grown crops.
In the project, we will address important issues related to the risks associated with plant viruses and viroids in the use of fertilisers from organic waste. We will develop efficient methods for the detection of plant pathogenic viruses and viroids in various organic waste fertilisers that can be used to assess the potential risk associated with the use of such products in agriculture and horticulture. Since the composition of the matrix can have a significant impact on the retention of viruses and viroids, the development of suitable virus concentration and enrichment and nucleic acids isolation methods for organic waste fertilisers is the first major aim of our study. In addition to targeted detection methods for monitoring plant pathogenic viruses and viroids, such as PCR-based methods, we will also use a non-targeted high-throughput sequencing approach, which will be particularly valuable for studying the virome of various organic waste fertilisers, including insect frass, which has not been adequately studied so far. Finally, our study will also determine the persistence of selected stable viruses and viroids in organic waste fertilisers. Our study will be the first to investigate the persistence of virus/viroid-infected plant material in insect frass. We will compare this with the efficiency of degradation during the composting process under strictly controlled conditions with defined substrate and inoculum concentrations and with degradation in the growing substrate alone.
The experienced research team will ensure the success of the project in terms of assessing the risk associated with the presence and survival of plant viruses and viroids in organic waste fertilizers. This will lead to proper risk assessment studies and consequently to the right control strategies and better crop protection, which is essential in a world with a growing population and increasing food demand and waste production.
The project received funding as small applied research project by Slovenian Research and Innovation Agency (ARIS). Co-financers of the project, besides ARIS, are Ministry of Agriculture, Forestry and Food (MKGP), BIA d.o.o and KOGAL d.o.o.
Partners in the project are National Institute of Biology (Slovenia), University of Ljubljana – Biotechnical Faculty (Slovenia), and BIA d.o.o (Slovenia). We will cooperate with University of Innsbruck (Austria) and CREA (Italy).
ARIS project ID: L4-60158
Duration: 1.1.2025 – 31.12.2027.
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