Evaluation of innovative promising fungicide from nitropyrazolone class: effects on phytopathogens and non-target organisms.

Abstract

The search for new fungicides is increasingly critical due to significant losses in crop quality and quantity caused by fungal diseases, as well as the development of resistance among pathogens to existing plant protection products. This study focuses on the evaluation of previously hardly known nitropyrazolone, 4,5-dimethyl-4-nitro-2-phenyl-2,4-dihydro-3 H-pyrazol-3-one, for its fungicidal properties. The antifungal activity of this compound was assessed against common phytopathogens, including Sclerotinia sclerotiorum, Alternaria alternata, Verticillium dahliae, and Fusarium graminearum, utilizing both in vitro and in vivo methods. Results indicated that the test compound effectively suppressed the growth of phytopathogens in laboratory tests, achieving maximum inhibition rates of 80% against S. sclerotiorum, minimum inhibition rates of 58% against V. dahliae, In vivo assessments conducted on cherry tomatoes demonstrated a 1.3-fold reduction in disease incidence caused by F. graminearum when treated with the test compound at a concentration of 0.01%. To evaluate the safety profile of the test compound concerning non-target organisms, phytotoxicity tests were performed on spring oats (Avena sativa) and radishes (Raphanus sativus), revealing no phytotoxic effects. Additionally, minimum inhibitory concentrations (MICs) were determined for common pathogens (Pseudomonas aeruginosa and Escherichia coli) and two strains typical of the soil microbial community, which are frequently used as biocontrol agents (Pseudomonas fluorescens and Bacillus subtilis). Thus, primary screening results suggest that the test compound has potential as an effective fungicide that does not exhibit toxicity toward plants or beneficial bacteria.