## 4 Discussion  
Without denying the economic benefits in the nearest future, scientists around the world are increasingly thinking about remote environmental and medical problems caused by the excessive use of pesticides [13; 24; 25]. This is evidenced by a huge number of studies of toxic, genotoxic, mutagenic, teratogenic effects of pesticides. However, there are still many gaps in the study of the effects of pesticides on non-target organisms. In particular, it concerns the influence of pesticides on phytopathogenic bacteria as non-target organisms. We have found that most pesticides in recommended concentrations have no significant effect on the growth of phytopathogenic bacteria but can show mutagenic activity against them [20]. However, data on this effect of pesticides on bacteria are limited and therefore studies on this issue do not lose their relevance. To carry out research, we have chosen the pathogen of tomato speck (the most used vegetable crop in Ukraine) because of its wide distribution in our country [5] and because _P. syringae_ are well known as epiphytes. Constantly being in the phyllosphere, bacteria of the _P. syringae_ type are influenced by all substances that are used for the treatment of tomato plantings. We identified that aluminium photethyl at the concentration of 400 mg/L and 40.0 mg/L is characterised by toxic effect on the pathogen of tomato bacterial spec _P. syringae_ pv. _tomato_. Deltamethrin at the concentration of 2.5 mg/L, 0.25 mg/L and 0.025 mg/L was characterised by low toxicity for both strains of _P. syringae_ pv. _tomato_. According to the literature data, deltamethrin insecticides have the genotoxic effects [26; 27; 28]. In these studies, it was shown that deltamethrin at the doses of 50, 100, 200 mg/kg/bw significantly increased the formation of micronucleeli in erythrocytes and splenocytes of mice at the 48 th hour after application. The greatest dose (200 mg/kg) was identified to have the greatest number of micronucleeli, and its difference from the control groups was found to be statistically significant (_p_ < 0.001). According to these results, it was determined that in acute toxic doses, deltamethrin showed genetic toxicity in somatic cells of mice and provided a slight and statistically insignificant induction in lower doses [27]. It has been established that using the commercial formulation of deltamethrin (Decis 25) cause the increase of micronucleeli (MN) frequencies in _T. rendalli_ at doses of 1.0 and 5.0 mg/kg, and in mice there was no MN induction [28]. Pyrethroids, including allethrin, bioallethrin, deltamethrin, and esbiothrin possessed weakly mutagenic potential with base-pair substitution in the Ames test. They also slightly induced DNA damage when assessed by the comet assay [29]. For the fungicide aluminium photethyl, no genotoxic effect was found [30; 31]. Another danger of pesticide use is the phenomenon of cross-resistance to pesticides and antibiotics [32]. According to scientists, resistance to pesticides contributes to the development of antibiotic resistance [33]. In our opinion, such antibiotic resistance can be a consequence of the mutagenic action of pesticides. Therefore, we studied the ability of aluminium photethyl and deltamethrin to induce resistance to streptomycin in the strains of _P. syringae_ pv. _tomato_. We found that aluminium photethyl fungicide does not cause an increase in the number of Str\({}^{\text{R}}\) colonies of strains of _P. syringae_ pv. _tomato_ on medium with streptomycin, while in terms of action of the insecticide deltamethrin, there was observed an increase in the number of Str\({}^{\text{R}}\) colonies of strains of _P. syringae_ pv. _tomato_. Thus, deltamethrin induced an increase in the frequency of formation of Str\({}^{\text{R}}\) mutants of _P. syringae_ pv. _tomato_. Similar activity was characteristic for another pyrethroid alpha-Cypermethrin against _P. syringae_ pv. _atrofaciens_[15].