# Effect of Pseudomonas Fluorescens on Isofetamid Dissipation and Soil Microbial Activity
## 1 Introduction  
Fungicides are a type of pesticide that is designed to eliminate or inhibit the growth of fungi in crops. In agriculture, they are used to reduce crop losses by preventing or combating plant diseases caused by fungi. Fungicides account for over 35% of the global pesticide market and their use is expected to increase over the years [1]. This is due to the fact that in modern agriculture, fungicides are extensively applied to mitigate the negative impact of fungal plant pathogens and produce high-quality food [2, 3]. Isofetamid (N-[1,1]-dimethyl-2-(4-isopropyl-o-tolyl)-2-oxoethyl]-3-methylthiophene-2-carboxamide), is a new generation of SDHI fungicide discovered by Ishihara Sangyo Kaisha (ISK), registered as a pesticide in 2014 and introduced in Japan in 2016. It is a broad-spectrum fungicide and is eagerly used by farmers and gardeners, e.g., in the cultivation of strawberries or lettuce [4, 5]. Another very important aspect for farmers, as stated in the leaflet of the Kenja 400 SC product, is the relatively short withdrawal (for lettuce, according to Australian recommendations, it is 7 days) [6]. Importantly, isofetamid can be mixed with most fungicides available on the market [4]. Its mode of action is to block the activity ofplant pathogens by inhibiting the ubiquinone binding site in mitochondrial complex II, which means that the process of developing resistance to the pathogen that causes grey mold is greatly limited by the direct adaptation of the active substance molecule to the structures of the fungus, with, as a result, the complete inhibition of its development [1; 4]. Studies have shown that isofetamid can effectively combat diseases caused by _Botrytis cinerea_ and _Sclerotinia sclerotorium_ in many plants, mainly fruits and vegetables [5]. Despite their fungicidal effect, the use of fungicides, including isofetamid, raises concerns about their impact on the environment and human health. Since it is a substance that is often used due to the above-mentioned beneficial properties of its use, it should be thoroughly tested in terms of its impact on the environment. Fungicides applied to plants can get into the soil, where they can undergo sorption processes; some can be lost through evaporation or leaching into groundwater [3; 7]. According to the PPDB (Pesticide Properties DataBase) [8], the toxicity profile of isofetamid is given as moderate for both the environment and human health. However, this does not mean that it is a safe substance and has no impact on the environment. It should be remembered that each active substance of a pesticide leaves behind some trace, which can irreversibly change the populations of the ecosystem even a long time after its application. Research is ongoing on the effects of isofetamid on non-target organisms, including plants and soil microorganisms. It is known that some fungicides can affect the biodiversity and activity of soil microorganisms. It has been shown that tebuconazole fungicides can inhibit the activity of dehydrogenase, phosphatases, urease and \(\beta\)-glucosidase [9]. This is, therefore, a premise for the need to seek methods to eliminate the negative impact of synthetic fungicides such as isofetamid, both in terms of plant health and soil health. One of them may be the application of microorganisms belonging to the PGPR group (Plant Growth-Promoting Rhizobacteria) [10]. The use of biological stimulants in the form of PGPR microorganisms in agricultural and environmental research is becoming increasingly common due to their potential properties related to improving plant growth and increasing resistance to biotic and abiotic stresses [11]. Their activity may be based on competition for food with pathogens, the production of substances that cause lysis of pathogen cell walls or the decomposition of pollutants [12]. PGPR may include various microorganisms that inhabit the rhizosphere zone, among which are _Azotobacter, Klebsiella, Enterobacter, Alcaligenes_ and _Bacillus_[13; 14; 15].