EFFICIENCY OF INTEGRATED USE OF BIOLOGICAL AND CHEMICAL AGENTS FOR TOMATO PLANT PROTECTION AGAINST FUSARIUM INFECTION

Compatibility of chemical and biological plant protection agents is an important factor in the effectiveness of biologicals. The study was conducted to investigate the compatibility of the microbial strains Pseudomonas aureofaciens BS 1393, Pseudomonas fluorescens WCS 365, Trichoderma asperellum T302 and Pseudomonas putida PCL 1760 with chemical pesticides mandipropamid and difenoconazole, as well as to evaluate their combined effect on the pathogenic fungus Fusarium oxysporum f. sp. radicis-lycopersici ZUM2407. The work was carried out at the laboratory in 2025. Experiments were conducted using two-section Petri dishes to assess the biological activity of volatile compounds. Microbial strains were cultivated in the first section, while a nutrient medium containing pathogen conidia or tomato seeds was placed in the second section to evaluate the growth- stimulating effect. Pesticide concentrations were used at reduced doses (2 times lower than those recommended by the manufacturer). Even at low pesticide concentrations, a synergistic effect was achieved in combination with antagonist microorganisms, ensuring effective pathogen suppression. Volatile compounds of the studied strains reduced germination of conidia of phytopathogenic fungus from 70.1% in the control to 10.8–14.2% in the experimental variants. Optimal combinations were identified: mandipropamid (2 ml/5 l) + P. putida PCL 1760 for stimulating vegetative growth, increasing stem length by 69%; and difenoconazole (2.5 ml/5 l) + P. aureofaciens BS 1393 for root development, increasing root length by 108.9%. P. aureofaciens BS 1393 demonstrated the highest resistance to the chemical components in the experiment. The obtained results are important for the development of environmentally friendly plant protection strategies.