Combinational use of biological control agents and novel bactericides in integrated pest management systems

The rapidly expanding global population has placed unprecedented pressure on agricultural systems to increase productivity while minimizing environmental impact. While the world&apos;s population steadily increasing, the need to ensure sustainable and resilient food production has never been more critical. In this context, pests and diseases pose significant challenges, undermining crop yields and compromising food security. The economic toll of plant diseases is staggering. Global crop losses due to diseases account for approximately 10-16% of total production annually. On the other hand, the list of plant protection products is further reduced due to apprehensions regarding residues in food and water, as well as their environmental consequences. However, it is not only safety that drives these restrictions, but also the ongoing requirement for novel chemical pesticides and resistant plant cultivars. Based on the information provided, it becomes evident that the transition towards alternative plant protection methods that are more environmentally friendly is unavoidable. Despite the accumulated knowledge in BCAs little is known about their interactions and their combinational ability with other plant protection products. Moreover, the industry evaluates BCAs mostly as fungicides rather than microorganisms, and they are not studied for their bactericidal efficacy. This doctoral thesis aims to provide significant knowledge regarding Biological Control Agents (BCAs), their interactions, and the colonization ability of BCAs in the presence of organic amendment and copper nanoparticles. The potential of combinational use of biological control agents and novel bactericides was studied by conducting comprehensive in vitro and in planta studies, field experiments, and data analysis, to elucidate the synergistic interactions between these components and optimize their integration into existing Integrated Pest Management frameworks. This research aims to provide evidence-based recommendations for sustainable and ecologically balanced pest management practices and safe food products. The efficacy of novel nano-based copper products (CuNPs) was tested in vitro against eight economically important plant pathogenic bacteria. Results indicate that CuNPs (5,23 and 10,41 nm) inhibited growth in lower concentrations compared to reference products (Nordox and Kocide). In addition, CuNPs were assessed in planta against Xanthomonas campestris pv. vesicatoria, causing agent of the bacterial spot disease of tomato. Pathogen population growth was delayed, in comparison to conventional copper compounds (Nordox), at the first stage of disease development. This fact suggested a superior efficacy for CuNPs. X-ray fluorescence spectrometry (XRF) measurements of tomato leaves correlated the bioavailability of copper to bactericidal efficacy. It is reported, for the first time, that the bioavailability of copper is higher in the case of nanoparticles, compared to conventional copper bactericides, and is dependent on synthesis method rather than size. To evaluate the combinational ability of the commercial strain B. amyloliquefaciens MBI600 (Serifel) with TriaAlfa Essence, a commercial Organic amendment, in vitro growth tests were performed. In addition, MBI600 population growth was monitored on leaves and fruits of vineyard, cherry, orange, and tomato crop in field experiments using two different methods: the number of colony-forming units (CFUs) and the quantitative Real-Time PCR method. Results showed that TriaAlfa significantly enhanced MBI600 colonization on fruits of vineyards. Also, comparing the two methods of assessment, a significant difference in the MBI600 population was observed when TriaAlfa was supplemented in the higher concentration of 1 L/ acre Real-Time PCR method was used in contrast to dilution plating (CFUs).