Fruit growing
and viticulture of South Russia
Yakuba Galina
Articles in journal: (total 18)
The data of research that reveal the mechanisms of phytosanitary control of fruit agrocenosis are presented. Research are directed on the decision of problems of biosystem ecologization connected with revealing of stability degree of myco- pato- entomocenosis of fruit orchard and strawberry on exogenous fluctuation reaction (weather factors, entering of pesticides, degree of intensity of gardening technology etc.).
With the climate change on the planet towards warming, the fungi of the genus Alternaria Nees became more active. Due to the prevailing climatic conditions, some species of this genus changed their status and acquired signs of facultative parasitism and complete parasitism on a number of cultivated plants, including the apple-tree. In vitro scientific studies are required to effectively control the disease, in the pathogenesis of which a large number of species are involved. At the same time, it is necessary to achieve fast and guaranteed growth of each of the fungus in the experiments. In this regard, the selection for fungi of the genus Alternaria, causative agents of apple fruits core rot, optimal for the cultivation of nutrient mediums is urgent. The studies were carried out by methods of laboratory and comparative analyzes. The growth of two strains of the causative agent of the apple fruit core rot of Alternaria alternata (Fr.) Keissl. on 12 nutrient mediums. Colony growth rate and morphological and cultural traits were assessed. As a result of research the strains of apple fruit core rot agent, a variation not only in the growth rate of colonies, but also in their cultural characteristics, depending on the compositions nutrient medium. A comparative study of the morphological and cultural characteristics of A. alternata strains FR20IV and FR20VI on various nutrient mediums made it possible to identify three universal mediums most suitable for their cultivation and identification, namely carrot, potato agars and Sabouraud's medium, according to the following criterions: ensuring the maximum degree of sporulation, rapid growth and development of the mycelium of the fungus, as well as easiness of preparation of revealed optimum cultural mediums.
A method for assessing the virulence of the apple scab pathogen on unripe fruits is offered in the paper. The necessary conditions for its effective implementation were determined experimentally. It is shown that unripe fruits should be selected from the genotypes of apple-trees, which are controlled by chemical preparations for fungal diseases, in the "walnut" development phase. Surface disinfection of fruits is not effective if they are infected with rot agents in the garden, which may prevent of further analysis. The same conditions for the preparation and selection of unripe fruits should be observed when they are further stored for deferred experiments. The method was tested on 9 monospore isolates of Venturia inaequalis isolated from the apple variety of Renet Simirenko. The manifestation of symptoms of scab lesions was characterized by the development of diffuse spots of dark olive or dark gray color with mainly superficial development of pathogen mycelium. The studied isolates of V. inaequalis characterized by different levels of virulence and aggressiveness on different genotypes of the host plant, reflecting the high heterogeneity of the pathogen population. Pathogenicity of most isolates was higher for immature fruits from the variety Renet Simirenko, showing their adaptability to the variety from which they were isolated. Slightly lower virulence and aggressiveness of isolates was observed for the Idared apple variety. Only one of the 9 isolates of the scab pathogen was virulent to the species of Malus x purpurea var pendula ornamental apple. The study carried out showed the effectiveness of the proposed method, under the conditions of fruit selection, in assessing the virulence and pathogenicity of monospore isolates of the apple scab pathogen in laboratory conditions.
The results of the working out of the controle mechanisms by mycopathocenosis of an ap-ples garden are presented. The appearance of new kinds of the fungi that cause wood rot, demonstrates the need to assess their biodi-versity and occurrence. During the basis of results of monitoring of one type of fungal pathogen can predict the risk of another. For foothill zone horticulture the varieties are se-lected steady and high susceptible to the main diseases and strategies for their protection is determined.
As a result of studying sensitivity of an apple varieties to different origin of fungous disease in the conditions of Krasnodar region are allocated resistant and low-susceptible apple varieties which allows for the introduction to ensure non-polluting production, to reduce technogenic load by a garden biocenosis.