Currently, there is an active development of environmentally friendly methods of farming. However, the range of products for this type of farming system is limited. Growth stimulation is one of the mechanisms ensuring plant resistance to diseases that reduce crop yields. The aim of the work is to study the effect of laboratory samples of new biological products based on B. subtilis BZR 336 g, B. subtilis BZR 517, P. chlororaphis 245 F strains and organo-mineral fertilizers PRK White Pearl Brown (WPB) and PRK White Pearl Universal” (WPU) on plant growth and development of plants, as well as study of the possibility of their joint use for subsequent inclusion in organic farming systems or integrated plant protection. Growthpromoting ability was assessed in winter wheat and sunflower plants grown in sand in a climatic chamber. As comparison variants there were seed treatment with water (control), chemical (Dividend Star, KS) and biological (Fitosporin-M, F, B. subtilis 26 D) standards. In two plant cultures there was an expected retardant effect of the chemical standard and the growth-promoting effect of the biological standard. Statistically significant data were obtained for such a parameter as the shoot length. On winter wheat, laboratory samples provided the shoot length of 24.1-25.2 mm (an addition to the control of 3.4-8.2%), organic and mineral fertilizers - 23.9-24.5 mm (2.6-5.2%), mixtures with WPU - 23.2-24.4 mm (-0.4-4.7%), mixtures with WPB - 24.1-25.9 mm (3.4-11.2%), a significant increase in root length was not observed in this culture. On winter wheat, it is advisable to use the studied products separately. Sunflower is more responsive to the action of laboratory samples. They provided a shoot length of 13.6-14.6 mm (20.9-27.0%) and a root of 9.2-10.2 mm (4.5-15.9%). Organo-mineral fertilizers provided a shoot length of 14.2-14.5 mm (23.5-26.1%) and the root length of 10.8 mm (22.7%). Mixtures with WPU provided shoot length of 14.7-15.4 mm (27.8-33.9%), mixtures with WPB provided shoot length of 11.9-14.5 mm (3.5-26.1%), and no significant increase in root length was noted. The data obtained indicate the presence in the laboratory samples of fungicidal biological products growth-promoting properties, which vary depending on the culture and additionally used organic and mineral fertilizers. To confirm the results, additional experiments are necessary. Research in this direction will allow the rational use of the studied means of protection and increase plant yields in systems of organic, ecologized and integrated farming, and can help reduce the pesticidal pressure on agrocenoses.Conflict of interest: the authors stated that there was no conflict of interest.

As a result of stage screening, there were selected promising bacterial strains to create laboratory samples of biological products on their basis to protect winter wheat from the causative agents of fusarium root rot. The purpose of the work is to determine the growth-stimulating and protective effect of laboratory samples of Bacillus subtilis BZR 336g and B. subtilis BZR 517 on winter wheat plants, as well as to determine the antagonistic effect of strains on Fusarium fungi. As a result of the work, there was established a positive effect of laboratory samples on the growth, development and germination of plants in greenhouse conditions and the ability to significantly inhibit the mycelium of phytopathogenic fungi F. graminearun, F. culmorum and Microdochium nivale in laboratory conditions. The study of the samples artificially infected in a climatic chamber showed not only a high protective effect of these laboratory samples, but also made it possible to determine the regimes for their use. The conducted tests prove the viability of new bioagents as environmentally friendly plant-protective products.

As a result of a series of experiments to study the entomopathogenic activity of bacteria and viruses from the “State Collection of Entomoacariphages and Microorganisms”, it was revealed that the large wax moth Galleria mellonella L. it is sensitive to new strains of bacteria and viruses. In the future, the strains can be used in the subsequent stages of screening of microorganisms that are promising as agents of biological pest control. The maximum biological efficacy on the fifth day against the tested insect was observed when using bacterial strains Bacillus spp. BZR 1159 (94.6%) and BZR 936 (95.0%) and a granulovirus strain of the codling moth (CpGV) BZR L-5 (100%). Larvae of G. mellonella L were susceptible to melanization in the process of infection with new bacterial and viral agents.

Cydia pomonella granulovirus is a natural pathogen for Cydia pomonella that is used as a biocontrol agent of insect populations. The study of granulovirus virulence is of particular interest since the development of resistance in natural populations of C. pomonella has been observed during the long-term use of the Mexican isolate CpGV. In our study, we present the genomes of 18 CpGV strains endemic to southern Russia and from Kazakhstan, as well as a strain included in the commercial preparation “Madex Twin”, which were sequenced and analyzed. We performed comparative genomic analysis using several tools. From comparisons at the level of genes and protein products that are involved in the infection process of virosis, synonymous and missense substitution variants have been identified. The average nucleotide identity has demonstrated a high similarity with other granulovirus genomes of different geographic origins. Whole-genome alignment of the 18 genomes relative to the reference revealed regions of low similarity. Analysis of gene repertoire variation has shown that BZR GV 4, BZR GV 6, and BZR GV L-7 strains have been the closest in gene content to the commercial “Madex Twin” strain. We have confirmed two deletions using read depth coverage data in regions lacking genes shown by homology analysis for granuloviruses BZR GV L-4 and BZR GV L-6; however, they are not related to the known genes causing viral pathogenicity. Thus, we have isolated novel CpGV strains and analyzed their potential as strains producing highly effective bioinsecticides against C. pomonella.

The use of CpGV strains as the basis for bioinsecticides is an effective and safe way to control Cydia pomonella. The research is aimed at the identification and study of new CpGV strains. Objects of identification and bioinformatic analysis: 18 CpGV strains. Sequencing was carried out on a NextSeq550. Genome assembly and annotation were carried out using Spades, Samtools 1.9, MinYS, Pilon, Gfinisher, Quast, and Prokka. Comparative genomic analysis was carried out in relation to the reference genome present in the «Madex Tween» strain-producer (biological standard) according to the average nucleotide identity (ANI) criterion. The presence/absence of IAP, cathepsin, MMP, and chitinase in the genetic sequences of the strains was determined using simply phylogeny. Entomopathogenic activity was assessed against C. pomonella according to the criterion of biological efficacy. Thus, molecular genetic identification revealed that 18 CpGV strains belong to a genus of Betabaculovirus. For all the strains under study ANI values of 99% or more were obtained, and the presence of the cathepsin, chitinase, IAP, and MMP genes was noted. The strains BZR GV 1, BZR GV 3, BZR GV 7, BZR GV 10, and BZR GV L-8 showed the maximum biological efficacy: 100% on the 15th day of observation. Strains BZR GV 4, BZR GV 8, and BZR GV 13 showed efficacy at the level of the «Madex Tween» preparation: 89.5% on the 15th day of observation. The strains with the highest mortality rate of the host insect were identified: BZR GV 9, BZR GV 10, BZR GV L-6, and BZR GV L-8.

Apple scab (Venturia inaequalis) is a globally destructive disease of apple trees. Sustainable alternatives to synthetic fungicides are urgently needed. This study assessed the efficacy of five experimental bacterial-based formulations for controlling apple scab in two-year small-scale field trials. The experimental formulations containing Bacillus cereus BZR 736, Brevundimonas naejangsanensis BZR 1159, Achromobacter marplatensis BZR 926, Bacillus velezensis BZR 277, B. velezensis BZR 936 were applied to apple trees over the 2023-24 growing seasons. Treatments were sprayed five times per season and compared with water control and a commercial biofungicide (Fitosporin-M, SC 2.5 L/ha, containing Bacillus subtilis 26D). A comparative analysis of the 2023-24 data confirmed that the experimental formulations maintained stable efficacy even under elevated disease pressure. The formulations based on B. velezensis BZR 277 and B. velezensis BZR 936 consistently provided robust protection, with leaf efficacy exceeding 60.0% and fruit protection surpassing 59.0%. The formulation containing A. marplatensis BZR 926, which showed a positive trend in fruit protection, ultimately reaching an efficacy level comparable to the reference product. Conversely, the protective effect of the B. cereus BZR 736 formulation was unstable across seasons. Furthermore, B. naejangsanensis BZR 1159 demonstrated negligible activity against apple scab. These results highlight that B. velezensis BZR 277 and BZR 936 as the most promising candidates for the development of new, reliable biofungicides, which could significantly reduce dependence on chemical pesticides within integrated apple disease management programs.