METHODSFORINCREASING GRAPEVINE DISEASERESISTANCE USING THE EXAMPLE OF THEFERGANAVALLEY Usmanov Saminjon Olimovich

Аннотация

; This article reviews the main diseases of viticulture in the Fergana Valley and methods for combating them, as well as methods for increasing the genetic resistance of grapevines to diseases. The article analyzes the importance of agrotechnical measures, biological and chemical protection methods , and the selection of disease-resistant varieties in preventing diseases. Taking into account the climatic conditions and soil characteristics of the Fergana Valley , practical recommendations are given to increase grape yield and improveits quality. Keywords : Viticulture , diseases, tolerance, Fergana Valley, agrotechnics, biological protection, chemical protection, variety selection, vine, mildew, oidium, anthracnose, bacterial cancer, gray rot. Introduction; Grapes are one of the important branches of Uzbekistan's agriculture, and the Fergana Valley in particular has favorable climatic and soil conditions for grape growing. The valley's sunny days and temperate climate ensure that grapes are juicy and of high quality. However, diseases are a serious obstacle to obtaining high and high-quality yields in viticulture. Diseases not onlyreduce theyield, but also negatively affect its quality, andsometimes lead to the death of the entire crop. Therefore, increasing the resistance of grapevines to diseases and effectively combating them is an urgent task. These measures not only increase economic efficiency, butalso serve to protect theenvironment. Main part 1.Main diseases ofgrapes intheFergana Valley and theirdevelopment conditions In the conditions of the Fergana Valley, the following diseases are mainly common in grapes, each ofwhich has itsown specific development conditions:  Mildew ( Plasmopara viticola ): This disease is one of the most dangerous diseases, developing rapidly, especially in humid and cool weather conditions . It spreads rapidly in spring and early summer, when the air temperature is 12−25°C and there is constant humidity. It causes serious damage to leaves, branches and grape heads. Yellow-green spots appear onthe leaves, and later brown necrosis. Whitepowder is observed underthe leaves.  Oidium (powdery mildew, Erysiphe necator ): On the contrary, this disease spreads especially quickly in hot and dry weather . Optimal conditions are created when the air temperature is 20−30°C and the humidity is low. It forms a gray-white powder on the tops of the grapes and young shoots, which interferes with the photosynthesis process of the plant and leads to cracking ofthefruits.  Anthracnose ( Elsinoe ampelina ): Causes red-brown spots with reddish edges on leaves and branches, and deep cracks on fruits. This disease also becomes active in humid and warm weather , especially after spring rains. The affected areas become necrotic, leading to the death of plant parts. 106 INTERNATIONAL MULTIDISCIPLINARY JOURNAL FOR RESEARCH & DEVELOPMENT SJIF2019:5.2222020:5.5522021:5.6372022:5.4792023:6.5632024:7,805 eISSN:2394-6334 https://www.ijmrd.in/index.php/imjrd Volume12,issue06(2025)  Bacterial canker ( Agrobacterium vitis ): Causes the formation of growths (corns) on the vine, especially on the root collar and trunk . This disrupts the plant's nutrition and eventually causes it to wither. It is often transmitted through mechanical damage and can persist in the soil fora long time.  Gray rot ( Botrytis cinerea ): Severely damages the crop, especially in conditions of high humidity and air temperatures of 15−25°C . Gray powder and rot are observed on ripe grape heads. Thisdisease also sharply reduces theshelflife ofgrapes. 2.Agrotechnical methods ofcombating diseases Correct agrotechnical measures are of great importance in preventing diseases , as they increase the overall immunity of plants and create unfavorable conditions for the development of pathogens:  Proper soil management: Regular cultivation and weeding of vineyards reduces the transfer of pathogens (especially mildew spores) from soil to plant. Turning over the vines in the fall helps to eliminateoverwintering pests and pathogens.  Ventilation and pruning of vineyards: Good ventilation is ensured by not planting vines too thickly, forming the branches correctly, and removing excess branches. This reduces the moisture on the surface of the leaves and fruits, preventing the development of diseases such as mildew and gray rot. Regular removal of damaged and diseased branches, their removal from the vineyard, and burning will eliminatethesource ofinfection.  Nutrition: Providing a balanced nutrition for the vine , especially with potassium and phosphorus fertilizers, increases the plant's immunity to diseases. It is important to use nitrogen in moderation, as its excess can lead to excessive sugariness of the plants and an increased susceptibility to diseases. Microelements (boron, zinc, manganese) also increase the plant's resistance to stress.  Irrigation regime: It is important to follow a correct and regular irrigation regime. It is recomme