The data concerning the effects of pesticides of different nature on the phytopathogenic bacteria was examined and summarized. Without extensive research on the mechanisms of interaction between pathogenic bacteria and pesticides in the literature review a similar message about microorganisms of soil and phyllosphere are included. The bacteria can be suppressed permanently by pesticides with a mechanism of action that universally affects biological processes in living systems. Long-term storage, ease of use and fast visible effect are the advantages of synthetic pesticides remedies. But chemical pollution, shifts in the balance of ecosystems, unpredictable effects of chemical pesticides on non-target objects are the drawbacks. Stimulation of resistance response in plants is unifying factor for all types of biopesticides. This is realized through localization of the pathogen during infection, blocking its further penetration, distribution and reproduction. The results of the study of effects of plant protection products on the phytopathogenic bacteria of main crops are described. Among all tested pesticides, thiocarbamate fungicides demonstrated significant inhibitory action on phytopathogens, but their effect may be neutralized by other constituents of multicomponent preparations. Triazole fungicides affect the causative agents of bacterioses of crops at a dose of more than 1% of the active substance in the nutrient medium. Insecticides and herbicides have little or no effect on phytopathogenic bacteria; however they can enhance morphological dissociations of some Pseudomonas strains, thereby increasing their ability to survive. The disadvantage of many biopesticides against phytopathogenic microorganisms is the difference between their efficacy in vitro and in vivo that is why the desired result is not achieved in field condition. In addition, biological pesticides often lose their activity causing the problem of constant search for new active antagonists. The fact that the sensitivity of phytopathogenic bacteria to pesticides is strain-dependent should be considered in practice, particularly, assessment of the antibacterial action of various preparations should not be limited to a single bacterial strain.

A significant part of the used pesticides does not reach the target organisms and, while remaining in the agrophytocenosis, influences all living organisms in it. Having a toxic and often mutagenic effect, pesticides induce morphological and physiological changes in the cells of microorganisms and are the cause of phenotypic heterogeneity of their populations. However, the effect of pesticides on phytopathogenic bacteria as non-target microorganisms remains out of the field of view for most researchers. However, the use of pesticides can lead to expansion of the diversity of existing phytopathogens and, as a consequence, complications of identification of the pathogens, loss of resistance by plants varieties, and increased harm from diseases caused by them. This study is focused on the effect of pesticides used in tomato plantations on the causative agent of bacterial speck of this crop—Pseudomonas syringae pv. tomato. The studies were carried out using the methods of classical microbiology. The mutagenic action of pesticides was recorded, taking into account the increase of the number of streptomycin resistance mutations in bacteria in the case of pesticide action. It is established that the fungicide aluminium phosethyl is characterised by a bacteriostatic effect on P. syringae pv. tomato. Deltamethrin insecticide does not affect the growth of P. syringae pv. tomato. However, there is an increase in the frequency of streptomycin resistance mutations in both studied strains of P. syringae pv. tomato after using deltamethrin. It is shown that the frequency of occurrence of R (rough colonies) forms of P. syringae pv. tomato IZ28 and IZ46 after using deltamethrin increased by 100 times when in comparison to the frequency of spontaneous morphological dissociation, or smooth-to-rough (S-R) mutation, of these bacteria. Therefore, aluminium phosethyl is characterised by moderate bacteriostatic action against P. syringae pv. tomato. Deltamethrin does not influence the growth of the pathogen of tomato speck but increases the frequency of formation of Str^R mutants and R forms of phytopathogenic bacteria.

Ukraine is one of the largest producers of vegetable products in the world. The sustainable development of this industry in Ukraine is vital for the food security of many countries worldwide. Recently, farmers in Ukraine are facing the challenge of increasing the number and severity of bacterial diseases. This problem is getting particularly harsh in the production of vegetables. The changing climatic conditions in many regions contribute to the increase of the aggressiveness of bacterial pathogens. Ukraine is also experiencing the negative consequences of rising temperatures, changes in the amount and quality of precipitation, and stronger winds. These factors facilitate the changes of stable regions of the spread of bacterial pathogens. In Ukraine, they result in the emergence, successful acclimatization and spread of new bacterial pathogens of vegetable crops, in particular, Ralstonia solanacearum. The growing risk of bacterial diseases in vegetable production requires the development of new strategies to control their causative agents, which should, at the same time, meet the requirements of environmental safety. This paper is aimed to analyse the potential of plant growth-promoting bacteria (PGPB) based bioformulations to control bacterial diseases of vegetable crops in Ukraine. Farmers in Ukraine, who are engaged in growing vegetables, feel lack of biocontrol compositions against the causative agents of bacterial diseases because the range of biocontrol agents with antibacterial activity approved for use in the country is limited. The most commonly used plant protection products in Ukraine are represented by the preparations based on bacteria of the genera Bacillus and Pseudomonas. Most of such products on the market are those developed and manufactured in Ukraine. Under given circumstances, the use of inoculants based on PGPB to control bacterial diseases of vegetable crops in Ukraine, as well as globally, seems very promising. Such biocontrol agents prevent contamination of plants with phytopathogens by inducing acquired systemic resistance and stimulating their growth and better productivity. Seed inoculation is a promising way of using PGPB in crop production. The market of bioformulations for vegetable farming in Ukraine is represented by products with a limited shelf life. It still experiences a shortage of up-to-date preparation forms that would ensure the long-term viability of PGPB and a prolonged activity of the compositions based on them. Thus, the development and introduction of encapsulated PGPB nanopreparations may contribute to solving the problem of biological control of pathogens of bacterial diseases of vegetable crops in Ukraine.

The aim of this study was the identification of the causative agent of the basal glume rot of wheat Pseudomonas syringae pv. atrofaciens from the affected weeds in wheat crops, and determination of its virulent properties. Isolation of P. syringae pv. atrofaciens from weeds of wheat crops was carried out by classical microbiological methods. To identify isolated bacteria, their morphological, cultural, biochemical, and serological properties as well as fatty acids and Random Amplification of Polymorphic DNA (RAPD)-PCR (Polymerase chain reaction) profiles with the OPA-13 primer were studied. Pathogenic properties were investigated by artificial inoculation of wheat plants and weed plants, from which bacteria were isolated. For the first time, bacteria that are virulent both for weeds and wheat were isolated from weeds growing in wheat crops. It was shown that the fatty acids profiles of the bacteria isolated from the weeds contained typical for P. syringae pv. atrofaciens fatty acids, in particular, hydroxy acids: 3-hydroxydecanoic, 2-hydroxydodecanoic, and 3-hydroxydodecanoic. RAPD-PCR profiles of the newly isolated strains were identical to those of the collection strains P. syringae pv. atrofaciens UCM B-1011 and P. syringae pv. atrofaciens UCM B-1014 and contained a dominant fragment of 700 bp. The isolated strains, according to their phenotypic and genotypic properties, were identified as P. syringae pv. atrofaciens. It was established that the causative agent of basal glume rot of wheat P. syringae pv. atrofaciens is polyphagous and capable of infecting a wide range of plants. The main control measure for cereals diseases caused by P. syringae pv. Atrofaciens—crop rotations with nonhost species, should be revised, and alternative control methods must be proposed.

Sodium nitroprusside is a well-known nitric oxide donor applied in plant cultivation. However, the problem of using sodium nitroprusside for protecting veg