Relevance. Tomato is one of the most beloved and popular vegetables among Primorye residents. But in the monsoon climate, the Far Eastern Primorye has the most intense infectious background in Russia. The yield losses of tomato fruits from alternariosis annually amount to 30% or more. Losses from late blight on the background of epiphytotics in years with wet and cold summers, as observed in 2019, depending on the stability of the variety, can reach from 17 to 100%. Despite the fact that the development and use of biological means of control has recently been a priority, it is still too early to abandon chemical protection measures. High efficiency and versatility of the correctly selected scheme of application of fungicides, short processing time – all this gives a quick and reliable result in protecting tomato crops and reducing the harmfulness of the complex of diseases.Methodology. The research was carried out in 2019-2021 at the Primorsky Vegetable Experimental Station (PVES) – a branch of the Federal Scientific Vegetable Center in the monsoon climate of the coastal zone of Primorsky Krai. We studied the effect of chemical preparations Signum, Orvego and their tank mixture with igum + Orvego on the development of diseases, yield indicators and the structure of the tomato crop varieties Odyssey, and Fitilek. Agrotechnics of cultivation are generally accepted in Primorsky Krai for tomato culture.Results. Testing of chemical fungicides in the conditions of Primorsky Krai showed that the development of alternariasis, starting with the appearance of the first signs of damage in the first half of the growing season, effectively restrains the fungicide Signum, contributing to the preservation of the working leaf surface. It is advisable to use the tank mixture With igum + Orvego starting from the first or second decade of August, when a complex of phytopathogens develops on the leaf surface. The introduction of these two fungicides into the tank mixture leads to an increase in the biological and economic effectiveness of protective measures in the fight against alternariasis and late blight of tomatoes, compared with the standard fungicide Acrobat MC. Joint Signum Processing+Orvego, by reducing the intensity of disease development and the share of the non-commodity part of the crop, has a beneficial effect on the mass of commercial fruit and contributes to a more complete realization of the productive potential of Odyssey and Fitilek varieties.

Relevance. The use of chemical fungicides in protecting plants from pathogens is the most common way, despite the proven danger of pesticides. The use of biofungicides based on essential oils of medicinal plants, which also have phytoncidal properties, can be a suitable alternative to chemical preparations. In the years favorable for the development of alternariosis or cladosporiosis, spots appear on the plants, leading to necrosis and significant loss of seed productivity. Therefore, the search for new effective and safe means of combating fungal phytopathogens becomes relevant.Methods. Alternaria alternata (2018-1.1) and Cladosporium cladosporioides (2019-11.4) strains were isolated from leaves with signs of alternariosis and cladosporiosis, on which the essential oils Abies alba, Artemisia vulgaris, Caryophyllus aromaticus, Coriandrum sativum, Lavandula officinalis, Ocimum basilicum, Pimpinella anisum, Rosmarinus officinalis, Salvia sclarea, Thymus vulgaris. The antifungal activity of essential oils was evaluated by comparing the diameter of the experimental (with the addition of essential oil to the Petri dish) and control colonies using the author’s scale.Results. All studied essential oils had antifungal properties, but species-specificity was observed. Essential oils of basil, coriander and thyme showed a fungicidal effect on C. cladosporioides and A. alternata. Lavender oil proved to be a fungicide for A. alternata and a strong fungistatic for C. cladosporioides. To create biological products for plant protection against alternariosis, sage essential oil (moderate fungistatic effect) may also be of interest, and cladosporiosis - anise and rosemary oils.

Relevance. Peanut seeds are rich in oils, protein, carbohydrates, vitamins and flavonoids, therefore they are widely used in the production of food, feed, biodiesel, as well as in medicine. When cultivating peanuts, the problem of reducing the yield and sometimes the quality of seeds necessarily arises due to the impact of phytopathogenic microscopic fungi, and the main factors in the transmission of the infectious principle are soil and plant residues. The plant protection system should be based on knowledge of the structure of mycocomplexes of the rhizosphere and phylloplane.Methods. On a typical black soil on a natural infectious background in Belgorod (Russia), a sample of cultural peanuts V-2012 (Vietnam) from the collection of the Department of Biotechnology and Microbiology of the Institute of Pharmacy, Chemistry and Biology of the National Research University "BelSU" was studied. The species composition of microscopic fungi in the peanut rhizosphere was analyzed in comparison with fallow soil (control), which was found by seeding soil dilutions and leaf samples on dense nutrient media, followed by identification to species.Results. Compared with the control soil, the mycocomplex of the peanut rhizosphere (the Shannon index value at the level of 2.5 and 2.7 in the rhizosphere and control, respectively) was characterized by a lower degree of diversity and the degree of similarity of soil samples was high (the Jaccard coefficient was 50%), which means that that the cultivation of peanuts has lit- tle effect on the composition and structure of a typical black soil. In the peanut rhizosphere, a decrease in the frequency of occurrence of the phytopathogenic species F. oxysporum was observed, which may be associated with an increase in the rank in the mycocomplex of the mycophilic species T. lignorum. Aspergillus ochraceus, A. terreus, A. ustus, Candida albicans, Curvularia lunata, Fusarium oxysporum, Trichothecium roseum species were found to be sen- sitive to peanut cultivation. Peanut leaf spot was caused annually by the species Alternaria alternate, which can lead to a decrease in seed productivity up to 80%.