Fruit growing
and viticulture of South Russia

Annotation

In recent years, there has been an increasing of the economical importance of diseases of the vascular system of grapes all over the world. The main pathogens are specialized fungal pathogens, the so-called ESCA complex. These fungi cause various types of necrosis. The affected plants have a growth delay, shortening of internodes, intercellular chlorosis, and a reduction of the growth of the young shoots. Disease outbreaks are usually finished with the death of the vine after a few years. The severest form of the disease � is apoplexy, which leads to the death of plants in just a few days. The consequences of the disease are the grape plantations productivity dropping. Fully disease-resistant cultivated or wild vine taxa do not currently exist. Biotechnology is the main global trend of the modern grapes protection (in the nurseries and exploited plantations), as well as in all fields of the plant growing. A sufficient number of scientific Publications have been devoted to the development of adaptive-integrated protection systems based on using of maximum possible non-chemical means of limiting or controlling t rachemicosis infection. In the world`s scientists` researches several solutions have been proposed: physical and biological ways to fight pathogens, and increasing in the resistance of plants themselves. The producers based on various Trichoderma strains among the biological methods that are widely used. They are used at all stages of reproduction in the nursery: soaking cuttings, fusion of the scion and rootstock, rooting. Studies of other authors have shown the ability of combinations of different strains of Pythium oligandrum to colonize the grapes roots and induce the protective reactions of the plant. Endophytic bacteria are also promising producers that suppress the development of the disease. All of these producers represent the opportunity to solve the problem of infection with tracheomycosis in nurseries and vineyards.

Annotation

Worldwide studies conducted on various crops, including grapes, show the expansion of the species diversity of mycopathogens due to the appearance of new species. It is reported about the species Alternaria Nees, Fusarium Link, Aspergillus P. Micheli ex Haller, Penicillium Link, Cladosporium Link with pathogenic properties for plants on which they have not been detected before. These fungi cause leaf spotting and exist in pathocomplexes, the structures of which differ depending on the culture, the affected organ, and phenological phase. A complex of fungi was found on the grapes, which causes necrosis of the leaves and serious damage to the photosynthetic apparatus of the plant. A strong development of the disease leads to the death of the leaf plate. In our study, 13 species of fungi isolated from necrotic leaves were found. The dominant fungi are Alternaria Nees, the common Aspergillus niger Tiegh., Mucor Fresen., Fusarium Link. Minor Components are Penicillium Link, Aspergillus flavus Link, Trichoderma Pers., Cladosporium Link. The composition of the mycopathocomplex is dynamic, varies depending on the phenological phase and abiotic conditions. Aspergillus niger Tiegh and Fusarium Link is found on young leaves with necrotic damages together with Alternaria fungi. In hotter and drier July, the number of Aspergillus fungi increases, but the percentage of occurrence of Alternaria and Fusarium decreases. In August-September, on old and weakened leaves, Mucor Fresen was much more common in the mycopathocomplex, which may indicate its necrotrophy in relation to grapes.

Annotation

The growing economic importance of alternaria fungi for agricultural crop production every year more and more activates research in the biology, ecology, and systematics of these micromycetes. By reducing the photosynthetic potential, pathogenic species of the genus Alternaria on vegetating plants cause slow destruction of host tissues. Small-spore species are mentioned as pathogens of alternarioses of various agricultural crops: A. alternata (Fries) Keissler, A. tenuissima & T. Nees: Fr.), A. infectoria and A. avenicola in the study of micromycete cultures and the selection of optimal nutrient media in vitro. For alternaria fungi, such screening can be carried out according to the criterion of the yield of the fungus biomass (g/100 ml of medium). According to some researchers, the most favorable for these purposes are the potato-glucose and Chapek environment. Since an important diagnostic feature of Alternaria is the structure of conidia, habitus and pattern structure, according to other researchers, too nutritious media should not be used for the cultivation of these fungi, as there is a suppression of the development of conidia. For example, Simmons (2007) recommends potato-carrot agar and agar medium V8.For the cultivation of fungi from the pathocomplex of necrotic leaf spot of grapes of the genus Alternaria, the optimal nutrient medium is potato-carrot agar (KMA). On this medium, there is sufficient, but not too abundant sporulation and moderate development of vegetative mycelium. CMA is also an optimal substrate for establishing the diversity of cultural traits of strains within a species for possible differentiation by strain trait, which is important for further population studies.

Annotation

Alternaria fungi affect a wide range of crops. Of the 300 known species of Alternaria fungi, more than 10 are serious pathogens. Alternariosi mainly manifested of leaf spot. The morbidity of plant by alternariosis is accompanied by high economic losses of agricultural products. In the vineyards of the South of Russia, a harmful manifestation of Alternaria spotting has been observed since the middle of the two thousand years. The causative agent of grapes alternariosis is semi-parasitic fungus of Alternaria tenuissima (Kunze ex Pers.) Wiltshire. The data of laboratory screening for the antimicotic activity of 8 chemical and 19 bacterial (based on bacterial and fungal antagonists) fungicides against the pathogen of Alternaria tenuissima grape � 12 straits of 7 types of bacteria and 7 straits of 4 types of fungi are presented in the article. The majority experimental variants of the active substances and their combinations in chemical fungicides showed the high efficiency in suppressing the growth of pathogen colonies. When comparing the antifungal activity of 2 concentrations of working solutions of biological preparations, it was found that bacterial fungicides show the best efficiency at a concentration of 4.0 ml / l, and fungal � at a concentration of 2.0 ml / l. Among bacterial strains-producers, B. amyloliquefaciens KC-2 B-11141 and B. subtilis var niger B-118 are the most effective in suppressing tenuissima. The strains of B. subtilis B-117, B. subtilis BS-1, B. subtilis B-522 and B. acidocaldarius B-5250 had low antifungal activity, 6 strains were not active. Among the fungal producer strains that participated in the screening for antimycotic activity, T. viride F-838 and T. viride F-294 have the highest efficiency.

Annotation

Krasnodar region is the leading region of Russia in the production of grapes, one of the most important branches of production in the world. In the region, about 80% of the area is occupied by technical varieties. Fungal diseases, in particular leaf spots, cause significant damage to viticulture, as they can lead to a significant decrease in yield capacity. One of these diseases is necrotic leaf spot caused by fungi of the genus Alternaria Nees. The article provides an assessment of the incidence of hybrid forms of this disease. In the conditions of 2019, which was characterized by elevated average monthly temperatures during the growing season, the greatest spread of the disease was observed on hybrid forms of Tana 19 and Tana 92, on which the pathogen was present in a parasitic form. In the conditions of a later start of vegetation in 2020, the intensity of disease development was low on all varieties (0.7-12.3 %). In 2022, there was a shortage of precipitation in several months of the growing season, as a result of which the pathogen spread less on all hybrid forms and was present mainly as a saprotroph on weakened leaves. The spread and intensity of the disease development differed depending on the shoot tier � the most severe leaf damage is noted on older leaves of the lower tier, the least � on young, or leaves of the upper tier. Tana 92 was characterized by the greatest infestation of leaves of the middle and lower tier among all forms. When analyzing the mycopathocomplex of necrosis on the leaves of hybrid forms, it was found that it contains 8 species of hyphomycetes, of which 50 % are different species of Alternaria.